Tornado
A tornado is a violently rotating column of air that is in contact with both the surface of the Earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. It is often referred to as a twister, whirlwind or cyclone, altho ...
es are more common in the United States than in any other country or state.
The
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
receives more than 1,200 tornadoes annually—four times the amount seen in Europe.
Violent tornadoes—those rated EF4 or EF5 on the
Enhanced Fujita Scale
The Enhanced Fujita scale (abbreviated as EF-Scale) rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States, Canada, China, and Mongolia.
The Enhanced Fujita scale repla ...
—occur more often in the United States than in any other country.
Most tornadoes in the United States occur east of the
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
. The
Great Plains
The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...
, the
Midwest
The Midwestern United States, also referred to as the Midwest or the American Midwest, is one of four Census Bureau Region, census regions of the United States Census Bureau (also known as "Region 2"). It occupies the northern central part of ...
, the
Mississippi Valley
The Mississippi River is the List of longest rivers of the United States (by main stem), second-longest river and chief river of the second-largest Drainage system (geomorphology), drainage system in North America, second only to the Hudson B ...
and the southern United States are all areas that are vulnerable to tornadoes. They are relatively rare west of the Rockies and are also less frequent in the northeastern states.
Tornado Alley
Tornado Alley is a loosely defined area of the central United States where tornadoes are most frequent. The term was first used in 1952 as the title of a research project to study severe weather in areas of Texas, Louisiana, Oklahoma, Kansas, So ...
is a colloquial term for an area particularly prone to tornadoes. There is no officially defined 'Tornado Alley' – at its broadest this area stretches from northern Texas to Canada with its core centered on
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
,
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
and northern
Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
. Another highly significant region – colloquially known as
Dixie Alley
"Dixie Alley" is a colloquial term sometimes used for areas of the southern United States which are particularly vulnerable to strong to violent tornadoes. Some argue this is distinct from the better known "Tornado Alley" and that it has a high f ...
– is the southern United States and particularly the northern and central parts of
Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
and
Mississippi
Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...
.
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
is one of the most tornado-prone states. However, Florida tornadoes only rarely approach the strength of those that occur elsewhere.
Although favorable conditions for tornadoes in the United States can occur at any time, they are most common in spring and least common in winter.
Because spring is a transitional period for the climate, there are more chances of cooler air meeting with warmer air, resulting in more thunderstorms. Tornadoes can also be spawned by
landfall
Landfall is the event of a storm moving over land after being over water. More broadly, and in relation to human travel, it refers to 'the first land that is reached or seen at the end of a journey across the sea or through the air, or the fact ...
ing
tropical cyclone
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
s, which usually occur in late summer and autumn. In the United States, thunderstorms capable of producing tornadoes usually form when the temperature is at its highest, typically from 4:00 p.m. to 7:00 p.m.
Although the period in which most tornadoes strike ("
tornado season
Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as we ...
") is March through June, tornadoes – including violent tornadoes and major tornado outbreaks – have been documented in the United States during every month and day of the year.
Two examples of this are when a series of tornadoes hit the state of
Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
on November 22, 1992, and injured at least nine people.
Another notable non-season tornado was where a tornado struck the area of
McLean County, Illinois
McLean County is the largest county by land area in the U.S. state of Illinois. According to the 2010 census, it had a population of 169,572. Its county seat is Bloomington. McLean County is included in the Bloomington–Normal, IL Metropolita ...
. Even though the tornado was during a winter month, it blew 20 railroad cars off their tracks, and hauled a camper over 100 yards (91 m).
During the winter months of the year, tornadoes have been known to hit the
Southern United States
The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, the Southland, or simply the South) is a geographic and cultural region of the United States of America. It is between the Atlantic Ocean ...
and
Southeastern United States
The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern por ...
the most, but have hit other areas as well.
One notable recent example of a winter tornado outbreak was the
2008 Super Tuesday tornado outbreak
The 2008 Super Tuesday tornado outbreak was a deadly tornado outbreak which affected the Southern United States and the lower Ohio Valley on February 5 and 6, 2008. The event began on Super Tuesday, while 24 states in the United States were hol ...
on February 5 and February 6, 2008. 84 tornadoes occurred over the course of the outbreak. The storm system produced several destructive tornadoes in heavily populated areas, most notably in the
Memphis metropolitan area, in
Jackson, Tennessee
Jackson is a city in and the county seat of Madison County, Tennessee, United States. Located east of Memphis, Tennessee, Memphis, it is a regional center of trade for West Tennessee. Its total population was 68,205 as of the 2020 United States ...
, and the northeastern end of the
Nashville metropolitan area
The Nashville metropolitan area (officially, the Nashville-Davidson–Murfreesboro–Franklin, TN Metropolitan Statistical Area) is a metropolitan statistical area centered on Nashville, Tennessee, the capital and largest city in Tennessee, in the ...
. At least 57 people were killed across four states and 18 counties, with hundreds of others injured.
The outbreak was the deadliest of the modern
NEXRAD
NEXRAD or Nexrad (Next-Generation Radar) is a network of 160 high-resolution S-band Doppler weather radars operated by the National Weather Service (NWS), an agency of the National Oceanic and Atmospheric Administration (NOAA) within the United ...
doppler radar era, until the
2011 Super Outbreak
The 2011 Super Outbreak was the largest, costliest, and one of the deadliest tornado outbreaks ever recorded, taking place in the Southern, Midwestern, and Northeastern United States from April 25–28, 2011, leaving catastrophic destruction ...
killed over 348 people (324 of which were tornado-related). It was the deadliest single outbreak since the
May 31, 1985 outbreak, which killed 76 across
Ohio
Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...
and
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
, as well claiming 12 victims in
Ontario
Ontario ( ; ) is one of the thirteen provinces and territories of Canada.Ontario is located in the geographic eastern half of Canada, but it has historically and politically been considered to be part of Central Canada. Located in Central Ca ...
, Canada. It was also the deadliest outbreak in both
Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
and
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...
since the
1974 Super Outbreak
The 1974 Super Outbreak was the second-largest tornado outbreak on record for a single 24-hour period, just behind the 2011 Super Outbreak. It was also the most violent tornado outbreak ever recorded, with 30 F4/F5 tornadoes confirmed. From Apri ...
.
Usually, tornadoes hit specific areas of the United States in specific seasons. During the winter months, tornadoes are usually spotted in the Southern area of the country, as well as states near the
Gulf of Mexico
The Gulf of Mexico ( es, Golfo de México) is an oceanic basin, ocean basin and a marginal sea of the Atlantic Ocean, largely surrounded by the North American continent. It is bounded on the northeast, north and northwest by the Gulf Coast of ...
.
This is due to cold air moving southward reaching its southern limit of expansion, and stopping over the
Gulf Coast
The Gulf Coast of the United States, also known as the Gulf South, is the coastline along the Southern United States where they meet the Gulf of Mexico. The coastal states that have a shoreline on the Gulf of Mexico are Texas, Louisiana, Mississ ...
.
As spring comes, hot air progressively moves back into the Gulf Coast. This pushes the mass of colder air forward out of the Gulf States and into the Southeastern states, where tornado frequency is highest in April.
As spring passes and summer begins, the mass of warm moist air moves northwest into the
Great Plains
The Great Plains (french: Grandes Plaines), sometimes simply "the Plains", is a broad expanse of flatland in North America. It is located west of the Mississippi River and east of the Rocky Mountains, much of it covered in prairie, steppe, an ...
and Midwestern states.
During the months of May and June, tornado activity is as its peak in the southern Great Plains. The air mass then moves northward into the Northern Great Plains and the
Great Lakes
The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes in the mid-east region of North America that connect to the Atlantic Ocean via the Saint Lawrence River. There are five lakes ...
area, causing a tornado activity peak in these areas during the summer months.
During the late summer and early fall months, tornado activity in the United States tapers off.
This is due to the relatively small difference between the temperature at the boundary of the hot air mass and the cool air mass at that time and an extension of the
Bermuda High
The Azores High also known as North Atlantic (Subtropical) High/Anticyclone or the Bermuda-Azores High, is a large subtropical semi-permanent centre of high atmospheric pressure typically found south of the Azores in the Atlantic Ocean, at the Hor ...
sitting over parts of the United States.
Though there may be some thunderstorms, they don't often become severe enough to spawn tornadoes.
Tornadoes may be formed out of season, especially during the months of
hurricane season in the Gulf Coast states and Southeastern states. Because these areas are prone to hurricanes, they may be struck with tornadoes that are spawned from hurricanes.
Tornadoes are most likely to form in the right-front quadrant of the hurricane, but can also form in rain bands associated with the storm.
This is caused by the large amount of vertical
wind shear
Wind shear (or windshear), sometimes referred to as wind gradient, is a difference in wind speed and/or direction over a relatively short distance in the atmosphere. Atmospheric wind shear is normally described as either vertical or horizontal ...
to the right of the storm. Tornadoes are also spawned from U.S. hurricanes due to the moistness of the air at the landfall of the storm, which makes conditions favorable for a
supercell
A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (s ...
storm to develop within the hurricane.
Regional activity
![Improved Average Annual Tornado Reports](https://upload.wikimedia.org/wikipedia/commons/5/5a/Improved_Average_Annual_Tornado_Reports.svg)
Tornadoes have been documented in every U.S. state (not including the non-state territories of
Guam
Guam (; ch, Guåhan ) is an organized, unincorporated territory of the United States in the Micronesia subregion of the western Pacific Ocean. It is the westernmost point and territory of the United States (reckoned from the geographic cent ...
, the
Virgin Islands
The Virgin Islands ( es, Islas Vírgenes) are an archipelago in the Caribbean Sea. They are geologically and biogeographically the easternmost part of the Greater Antilles, the northern islands belonging to the Puerto Rico Trench and St. Croix ...
,
American Samoa
American Samoa ( sm, Amerika Sāmoa, ; also ' or ') is an unincorporated territory of the United States located in the South Pacific Ocean, southeast of the island country of Samoa. Its location is centered on . It is east of the International ...
, and
Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and Unincorporated ...
) at least once since 1950, although some regions and states are hit by tornadoes far more than others.
For example, the average number of tornadoes to hit the states of
Alaska
Alaska ( ; russian: Аляска, Alyaska; ale, Alax̂sxax̂; ; ems, Alas'kaaq; Yup'ik: ''Alaskaq''; tli, Anáaski) is a state located in the Western United States on the northwest extremity of North America. A semi-exclave of the U.S., ...
,
Rhode Island
Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...
, and
Vermont
Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...
is less than one, while the state of
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
receives an average of 52 tornadoes per year, and the state of
Texas
Texas (, ; Spanish language, Spanish: ''Texas'', ''Tejas'') is a state in the South Central United States, South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2 ...
is hit with 126 tornadoes in an average year.
The state with the most tornadoes per unit area is
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
, though most are weak tornadoes of EF0 or EF1 intensity. A number of Florida's tornadoes occur along the edge of
hurricane
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
s that strike the state. The state with the highest number of strong tornadoes per unit area is
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
. States such as Oklahoma and Kansas have much lower population densities than Florida, so tornadoes may go unreported.
Midwest
The Midwestern states are very prone to tornado activity, as they are part of "
Tornado Alley
Tornado Alley is a loosely defined area of the central United States where tornadoes are most frequent. The term was first used in 1952 as the title of a research project to study severe weather in areas of Texas, Louisiana, Oklahoma, Kansas, So ...
."
States included in the area that are hit by tornadoes the most are
Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
,
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
,
Missouri
Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
,
Nebraska
Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...
,
Iowa
Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...
, and
South Dakota
South Dakota (; Sioux language, Sioux: , ) is a U.S. state in the West North Central states, North Central region of the United States. It is also part of the Great Plains. South Dakota is named after the Lakota people, Lakota and Dakota peo ...
.
The Midwestern States are often hit by tornadoes during the late spring and early summer months, especially the months of May and June.
This is due to the aforementioned air mass moving northward into the Midwest and combining with another air mass that move southward from
Canada
Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...
.
This creates unstable air, creating the potential for storms to strike the most during these months.
The frequency begins to decrease in the middle of the summer, as the air mass moves northward into the Great Lakes states.
A very notable recent storm that has hit this area was the Northwood, Kansas tornado, in the
May 2007 Tornado Outbreak
May is the fifth month of the year in the Julian and Gregorian calendars and is the third of seven months to have a length of 31 days.
May is a month of spring in the Northern Hemisphere, and autumn in the Southern Hemisphere. Therefore, Ma ...
. The tornado apparently strengthened as it neared Northwood, and at 9:38 pm CDT (0238 UTC), storm chasers reported that it had grown to over in diameter.
Several
satellite tornado
A satellite tornado is a tornado that revolves around a larger, primary tornado and interacts with the same mesocyclone. Satellite tornadoes occur apart from the primary tornado and are not considered subvortices; the primary tornado and satellite ...
es were observed as the very large wedge approached the town of Greensburg, Kansas. It was an estimated in diameter and was later confirmed to have been an EF5 on the
Enhanced Fujita Scale
The Enhanced Fujita scale (abbreviated as EF-Scale) rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States, Canada, China, and Mongolia.
The Enhanced Fujita scale repla ...
(the highest possible rating). Based on the damage produced, winds inside the tornado were estimated to have been in excess of .
Nebraska
Nebraska () is a state in the Midwestern region of the United States. It is bordered by South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Kansas to the south; Colorado to the southwe ...
is fifth overall for sheer numbers of tornadoes, while
Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
has had 88 violent tornado reports from the 1950–2006 period, more than any state except Oklahoma.
Iowa
Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...
reported 3,900 almost as many as Texas.
The deadliest tornado in US history, the
Tri-State Tornado
On March 18, 1925, one of the deadliest tornado outbreaks in recorded history generated at least twelve significant tornadoes and spanned a large portion of the midwestern and southern United States. In all, at least 751 people were ki ...
, struck
Missouri
Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
,
Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...
, and
Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
in March 1925.
St. Louis
St. Louis () is the second-largest city in Missouri, United States. It sits near the confluence of the Mississippi and the Missouri Rivers. In 2020, the city proper had a population of 301,578, while the bi-state metropolitan area, which e ...
, Missouri and neighboring
East St. Louis
East or Orient is one of the four cardinal directions or points of the compass. It is the opposite direction from west and is the direction from which the Sun rises on the Earth.
Etymology
As in other languages, the word is formed from the f ...
, Illinois have been hit more than once by violent tornadoes, the most notorious of which was the
St. Louis Tornado of May 1896. The
New Richmond Tornado
The 1899 New Richmond tornado was an estimated F5 tornado which formed on the early evening of Monday, June 12, 1899 and tore a 45-mile path of destruction through the St. Croix, Polk and Barron counties in west-central Wisconsin. It caused ...
of May 1899 and the
Flint, Michigan
Flint is the largest city and seat of Genesee County, Michigan, United States. Located along the Flint River, northwest of Detroit, it is a principal city within the region known as Mid Michigan. At the 2020 census, Flint had a population of 8 ...
tornado of June 1953 also rank amongst the deadliest tornadoes in US history.
The region was badly hit by the
Palm Sunday Tornado Outbreak in April 1965 and by the
Super Outbreak of April 1974. According to NCDC figures for the 1950 to 2006 period, Nebraska reported 2,440 tornadoes followed by Iowa (2,185), Illinois (2,086), Missouri (1,922), South Dakota (1,487), Minnesota (1,477), Indiana (1,327), North Dakota (1,216), Wisconsin (1,185), Michigan (981), and Ohio (916).
South
The
Southern United States
The Southern United States (sometimes Dixie, also referred to as the Southern States, the American South, the Southland, or simply the South) is a geographic and cultural region of the United States of America. It is between the Atlantic Ocean ...
has suffered more tornado fatalities than any other part of the country. Some areas experience repeated damaging tornado events, such as the Tennessee Valley and in northern
Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
. The state of Alabama is tied for the most reported F5 tornadoes.
For the period 1950 to 2006, three hundred and fifty eight people were killed by tornadoes in Alabama, ranking the state third nationwide behind Texas (521) and neighboring
Mississippi
Mississippi () is a state in the Southeastern region of the United States, bordered to the north by Tennessee; to the east by Alabama; to the south by the Gulf of Mexico; to the southwest by Louisiana; and to the northwest by Arkansas. Miss ...
(404).
Fourth is
Arkansas
Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...
(336) and fifth is
Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
with 271 fatalities.
Tornado disasters to affect the southern USA include the
Great Natchez Tornado
The Great Natchez Tornado hit Natchez, Mississippi on Thursday, May 7, 1840. This tornado was the second deadliest tornado in United States history; at least 317 people were killed and at least 109 were injured.
Event description
This massive ...
of May 1840 – second deadliest on record in the US, behind only the Tri-State Tornado.
Other outbreaks included the
Tupelo-Gainesville tornado outbreak of April 1936, the
1908 Southeast tornado outbreak of April 1908 and the
Candlestick Park Tornado
A destructive series of four tornadoes hit the Southeastern United States during March 3-4, 1966. The worst event was a violent and long-lived F5 tornado, dubbed the ''Candlestick Park tornado'' after the name of a recently-opened Jackson, M ...
of 1966. Alabama and
Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...
were very badly affected by the
Super Outbreak of 1974. The
2008 Super Tuesday tornado outbreak
The 2008 Super Tuesday tornado outbreak was a deadly tornado outbreak which affected the Southern United States and the lower Ohio Valley on February 5 and 6, 2008. The event began on Super Tuesday, while 24 states in the United States were hol ...
was the deadliest tornado outbreak in the US in 23 years.
58 people lost their lives with Tennessee, Arkansas, and Kentucky particularly badly affected. The
2011 Super Outbreak
The 2011 Super Outbreak was the largest, costliest, and one of the deadliest tornado outbreaks ever recorded, taking place in the Southern, Midwestern, and Northeastern United States from April 25–28, 2011, leaving catastrophic destruction ...
devastated much of the South, leaving 348 people dead.
Hurricanes and other tropical storms can also generate tornadoes.
Louisiana
Louisiana , group=pronunciation (French: ''La Louisiane'') is a state in the Deep South and South Central regions of the United States. It is the 20th-smallest by area and the 25th most populous of the 50 U.S. states. Louisiana is borde ...
and the coastal regions of Mississippi and
Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
are most at risk from these storms. The Atlantic seaboard states can be affected too. According to NCDC figures for the 1950 to 2006 period, Mississippi reported 1,787 tornadoes, followed by Louisiana (1,644), Alabama (1,608), Arkansas (1,579), Georgia (1,324),
North Carolina
North Carolina () is a state in the Southeastern region of the United States. The state is the 28th largest and 9th-most populous of the United States. It is bordered by Virginia to the north, the Atlantic Ocean to the east, Georgia and So ...
(1,042), Tennessee (892),
South Carolina
)''Animis opibusque parati'' ( for, , Latin, Prepared in mind and resources, links=no)
, anthem = " Carolina";" South Carolina On My Mind"
, Former = Province of South Carolina
, seat = Columbia
, LargestCity = Charleston
, LargestMetro = ...
(819), Kentucky (710) and
Virginia
Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...
(565).
West Virginia
West Virginia is a state in the Appalachian, Mid-Atlantic and Southeastern regions of the United States.The Census Bureau and the Association of American Geographers classify West Virginia as part of the Southern United States while the Bur ...
, by contrast, is one of the least vulnerable states of all with just 120 tornadoes reported over the period.
East and Northeast
The Northeastern U.S. to the east of the
Appalachian Mountains
The Appalachian Mountains, often called the Appalachians, (french: Appalaches), are a system of mountains in eastern to northeastern North America. The Appalachians first formed roughly 480 million years ago during the Ordovician Period. They ...
is much less vulnerable to violent tornadoes but is by no means immune. One of the most extraordinary tornadoes in history struck
Worcester, Massachusetts
Worcester ( , ) is a city and county seat of Worcester County, Massachusetts, United States. Named after Worcester, England, the city's population was 206,518 at the 2020 United States census, 2020 census, making it the second-List of cities i ...
.
This F4 tornado struck the city on 9 June 1953 and killed 90 people.
The tornado was generated by the
same storm system that hit
Flint, Michigan
Flint is the largest city and seat of Genesee County, Michigan, United States. Located along the Flint River, northwest of Detroit, it is a principal city within the region known as Mid Michigan. At the 2020 census, Flint had a population of 8 ...
with a
devastating F5 tornado that killed 116 people.
Areas further south – notably
Pennsylvania
Pennsylvania (; ( Pennsylvania Dutch: )), officially the Commonwealth of Pennsylvania, is a state spanning the Mid-Atlantic, Northeastern, Appalachian, and Great Lakes regions of the United States. It borders Delaware to its southeast, ...
and
Maryland
Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean to ...
– and areas to the west of the Appalachians are more vulnerable to tornadoes. NCDC figures for the period 1950 to 2006 show that Pennsylvania reported 697 tornadoes, followed by
New York State
New York, officially the State of New York, is a state in the Northeastern United States. It is often called New York State to distinguish it from its largest city, New York City. With a total area of , New York is the 27th-largest U.S. stat ...
(358), Maryland (269),
(153),
New Jersey
New Jersey is a state in the Mid-Atlantic and Northeastern regions of the United States. It is bordered on the north and east by the state of New York; on the east, southeast, and south by the Atlantic Ocean; on the west by the Delaware ...
(144),
Maine
Maine () is a state in the New England and Northeastern regions of the United States. It borders New Hampshire to the west, the Gulf of Maine to the southeast, and the Canadian provinces of New Brunswick and Quebec to the northeast and north ...
(101),
New Hampshire
New Hampshire is a U.S. state, state in the New England region of the northeastern United States. It is bordered by Massachusetts to the south, Vermont to the west, Maine and the Gulf of Maine to the east, and the Canadian province of Quebec t ...
(86),
Connecticut
Connecticut () is the southernmost state in the New England region of the Northeastern United States. It is bordered by Rhode Island to the east, Massachusetts to the north, New York to the west, and Long Island Sound to the south. Its cap ...
(82),
Delaware
Delaware ( ) is a state in the Mid-Atlantic region of the United States, bordering Maryland to its south and west; Pennsylvania to its north; and New Jersey and the Atlantic Ocean to its east. The state takes its name from the adjacent Del ...
(58),
Vermont
Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...
(37),
Rhode Island
Rhode Island (, like ''road'') is a U.S. state, state in the New England region of the Northeastern United States. It is the List of U.S. states by area, smallest U.S. state by area and the List of states and territories of the United States ...
(9), and the
District of Columbia
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...
(1).
The worst tornado outbreak in the Northeast occurred in Pennsylvania on
May 31, 1985, and produced the only F5 tornado in the region to date.
Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
is one of the most tornado prone states, with only Texas, Kansas and Oklahoma reporting more storms.
During the period 1950 to 2006, Florida reported 2,884 tornadoes according to NCDC figures.
However, Florida tornadoes are usually weak in comparison with those that strike the Plains and the Southern states – there have been only four reports of F4 strength tornadoes since 1950 and none of F5 strength.
Florida experiences more thunderstorms than any other state but fewer
supercell
A supercell is a thunderstorm characterized by the presence of a mesocyclone: a deep, persistently rotating updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of thunderstorms (s ...
storms.
Florida tornadoes are more often spawned by the frequent ordinary thunderstorms that occur over the state.
Hurricane
A tropical cyclone is a rapidly rotating storm system characterized by a low-pressure center, a closed low-level atmospheric circulation, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain and squalls. Depend ...
s and other tropical storms can generate large numbers of tornadoes. Non-supercell tornadoes are rarely as strong as supercell-generated storms.
Florida's most violent tornadoes generally occur during the winter months, when the state is most vulnerable to invasions of cold air that help generate such storms.
In recent years there have been some particularly disastrous tornado events. During the night of February 22 and 23, 1998, an F3 tornado struck
Kissimmee
Kissimmee ( ) is the largest city and county seat of Osceola County, Florida, United States. As of the 2020 census, the population was 79,226. It is a Principal City of the Orlando-Kissimmee-Sanford, Florida, Metropolitan Statistical Area, wh ...
and killed 25 people. Later that night, another F3 tornado struck
Seminole
The Seminole are a Native American people who developed in Florida in the 18th century. Today, they live in Oklahoma and Florida, and comprise three federally recognized tribes: the Seminole Nation of Oklahoma, the Seminole Tribe of Florida, an ...
and
Volusia
Volusia County (, ) is located in the east-central part of the U.S. state of Florida, stretching between the St. Johns River and the Atlantic Ocean. As of the 2020 census, the county was home to 553,543 people, an increase of 11.9% from the 2 ...
Counties and killed 13 people (see
Kissimmee Tornado Outbreak). On February 2, 2007, an EF3 tornado struck
Lake County with 21 fatalities resulting – see
2007 Central Florida Tornadoes
The 2007 Groundhog Day tornado outbreak was a localized but devastating tornado event that took place in central Florida early on February 2, 2007. Early morning temperatures had risen well above average for the season; combined with increased m ...
.
West and Southwest
Of the states around the
Rocky Mountains
The Rocky Mountains, also known as the Rockies, are a major mountain range and the largest mountain system in North America. The Rocky Mountains stretch in straight-line distance from the northernmost part of western Canada, to New Mexico in ...
,
Colorado
Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of t ...
reports by far the greatest numbers of tornadoes. Eastern Colorado, both climatically and physically, has much more in common with the neighboring Plains states of Kansas and Nebraska than with the mountainous areas further west. Small cities such as Limon, Kit Carson, Thurman, and Flagler are some places in Eastern Colorado that have experienced dangerous tornadoes. The same can be said, to a lesser extent, of eastern
Wyoming
Wyoming () is a U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho to the west, Utah to the south ...
. Tornadoes are less frequent in mountainous areas. Of the states in this region – according to NCDC figures for the 1950 to 2006 period – Colorado reported 1,617 tornadoes, followed by Wyoming with 560,
Montana
Montana () is a state in the Mountain West division of the Western United States. It is bordered by Idaho to the west, North Dakota and South Dakota to the east, Wyoming to the south, and the Canadian provinces of Alberta, British Columbi ...
(345),
Idaho
Idaho ( ) is a state in the Pacific Northwest region of the Western United States. To the north, it shares a small portion of the Canada–United States border with the province of British Columbia. It borders the states of Montana and Wyom ...
(175), and
Utah
Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...
(114).
In the
Southwestern United States
The Southwestern United States, also known as the American Southwest or simply the Southwest, is a geographic and cultural region of the United States that generally includes Arizona, New Mexico, and adjacent portions of California, Colorado, Ne ...
,
New Mexico
)
, population_demonym = New Mexican ( es, Neomexicano, Neomejicano, Nuevo Mexicano)
, seat = Santa Fe
, LargestCity = Albuquerque
, LargestMetro = Tiguex
, OfficialLang = None
, Languages = English, Spanish ( New Mexican), Navajo, Ker ...
reported 485 tornadoes during the 1950 to 2006 period (NCDC figures),
California
California is a U.S. state, state in the Western United States, located along the West Coast of the United States, Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the List of states and territori ...
reported 355,
Arizona
Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...
reported 209, and
Nevada
Nevada ( ; ) is a U.S. state, state in the Western United States, Western region of the United States. It is bordered by Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, and Utah to the east. N ...
reported 75.
New Mexico borders the notoriously tornado prone states of Texas and Oklahoma, hence the noticeably higher figures. Most of the tornadoes here happen in the very eastern part of the state. New Mexico's region and the desert landscape of the state help prevent the amount of twisters that happen in Oklahoma and Texas.
Arizona and New Mexico experience regular summer thunderstorms during their
monsoon
A monsoon () is traditionally a seasonal reversing wind accompanied by corresponding changes in precipitation but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with annual latitudinal oscil ...
season. These are sometimes tornadic but rarely produce violent tornadoes.
The
Pacific Northwest
The Pacific Northwest (sometimes Cascadia, or simply abbreviated as PNW) is a geographic region in western North America bounded by its coastal waters of the Pacific Ocean to the west and, loosely, by the Rocky Mountains to the east. Though ...
is perhaps the least vulnerable region. NCDC figures for the 1950 to 2006 period show that
Washington
Washington commonly refers to:
* Washington (state), United States
* Washington, D.C., the capital of the United States
** A metonym for the federal government of the United States
** Washington metropolitan area, the metropolitan area centered on ...
reported just 96 tornadoes for the entire period and that
Oregon
Oregon () is a U.S. state, state in the Pacific Northwest region of the Western United States. The Columbia River delineates much of Oregon's northern boundary with Washington (state), Washington, while the Snake River delineates much of it ...
reported 91.
However,
Portland, Oregon
Portland (, ) is a port city in the Pacific Northwest and the largest city in the U.S. state of Oregon. Situated at the confluence of the Willamette and Columbia rivers, Portland is the county seat of Multnomah County, the most populous co ...
and neighboring
Vancouver, Washington
Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington, located in Clark County. Incorporated in 1857, Vancouver has a population of 190,915 as of the 2020 census, making it the fourth-largest city in Was ...
were hit by a
deadly tornado on 5 April 1972. This storm was the deadliest to hit the United States that year.
Intensity
Tornadoes' damage varies based on their wind speeds and where they strike. The
Enhanced Fujita Scale
The Enhanced Fujita scale (abbreviated as EF-Scale) rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States, Canada, China, and Mongolia.
The Enhanced Fujita scale repla ...
classifies a tornado by its damage and then uses that classification to estimate the tornado's wind speed. For example, if it causes very little damage, then it is classified as an EF0 tornado and likely had very low winds. If damage from the tornado is severe enough, then it may be rated and likely had winds exceeding . In the United States, tornadoes have been known to form at high and low intensities. The probability of a high intensity or violent tornado differs by location across the country. For example, due to the high frequency of tornadoes in the "Tornado Alley" area mentioned before, a more violent tornado would be more likely to form there due to the strength of the thunderstorms produced by the two bordering air masses. The states with the highest number of F5 and EF5 rated tornadoes since data was available in 1950 are Alabama and Oklahoma, each with seven tornadoes. Iowa, Kansas, and Texas each are tied for second-most with six.
[ The state with the highest number of F5 and EF5 tornadoes per square mile, however, was ]Iowa
Iowa () is a state in the Midwestern region of the United States, bordered by the Mississippi River to the east and the Missouri River and Big Sioux River to the west. It is bordered by six states: Wisconsin to the northeast, Illinois to the ...
. The state with the most number of tornadoes classified as "violent", or F4 and F5, is Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...
, and the state with the highest average intensity ranking for tornadoes is Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
.
Tornadoes that are classified as EF4 and EF5 (or "violent tornadoes") on the Enhanced Fujita Scale
The Enhanced Fujita scale (abbreviated as EF-Scale) rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States, Canada, China, and Mongolia.
The Enhanced Fujita scale repla ...
only account for an average of two percent of all tornadoes in the United States each year. However, these high-intensity storms do account for an average of seventy percent of all tornado-related deaths in the United States each year. These storms can have winds of over and stay on the ground for over an hour.
The United States has seen 59 F5 and EF5 (the highest intensity and damage ranking) tornadoes since records began in 1950.[ No tornadoes prior to 1950 were officially ranked F5, due to inadequate engineering data and other information on the historical tornadoes. From 1950–1970 tornadoes were assessed retrogressively, primarily using information recorded in government databases, and newspaper photographs and descriptions. Beginning in 1971, tornadoes were rated by the NWS using on-site damage surveys.]
On May 3, 1999, a storm produced a violent tornado in the vicinity of Oklahoma City and was a part of the 1999 Oklahoma tornado outbreak
The 1999 Oklahoma tornado outbreak was a significant tornado outbreak that affected much of the Central and parts of the Eastern United States, with the highest record-breaking wind speeds of . During this week-long event, 154 tornadoes touched ...
, which also brought many violent storms to the states of Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
, Arkansas
Arkansas ( ) is a landlocked state in the South Central United States. It is bordered by Missouri to the north, Tennessee and Mississippi to the east, Louisiana to the south, and Texas and Oklahoma to the west. Its name is from the Osage ...
, and Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
. In total, the storm produced 66 tornadoes over four states. The strong F5 storm took place near the town of Bridge Creek, Oklahoma
Bridge Creek is a town in Grady County, Oklahoma, United States. As of the 2010 census, the town population was 336.
History
Bridge Creek was incorporated as a town in 2000. The town proper and the unincorporated areas that its limits enclose a ...
, located in Grady County. During the storm, a group of students in meteorology from the University of Oklahoma
The University of Oklahoma (OU) is a Public university, public research university in Norman, Oklahoma. Founded in 1890, it had existed in Oklahoma Territory near Indian Territory for 17 years before the two Territories became the state of Oklahom ...
had chased the storm on a Doppler on Wheels (or DOW), which scans storms while attached to a car. Doppler on Wheels data from the nearby storm revealed winds of , which was over the wind speed in the F5 classification of that time. Though the wind speed was over the F5 maximum, the tornado was not named the first ever F6 storm, as there was no F6 classification. Other scientists reviewed the DOW data taken by the students, and concluded that the estimated wind speed may have been inaccurate, but still over . Also, the wind speed recorded was taken from over above ground level. The National Weather Service also did a damage check, and found that the damage was that of an average F5 tornado.
Impacts
Injuries and fatalities
In the United States over 80 deaths and 1,500 injuries are associated with tornadoes each year.Statistics on the ten deadliest tornados in the US
Time. May 2011. According to the National Oceanic Atmospheric Administration
The National Oceanic and Atmospheric Administration (abbreviated as NOAA ) is an United States scientific and regulatory agency within the United States Department of Commerce that forecasts weather, monitors oceanic and atmospheric conditio ...
, most tornado deaths are caused by people not following instructions on what to do the right way. They also mention that some people are not even warned that a tornadic storm is coming, while others get a warning but do not believe that a tornado will hit their area. In 2012, 68 people were killed by tornadoes in the United States. Kentucky
Kentucky ( , ), officially the Commonwealth of Kentucky, is a state in the Southeastern region of the United States and one of the states of the Upper South. It borders Illinois, Indiana, and Ohio to the north; West Virginia and Virginia to ...
had the most fatalities, 22. Kentucky was followed by Indiana
Indiana () is a U.S. state in the Midwestern United States. It is the 38th-largest by area and the 17th-most populous of the 50 States. Its capital and largest city is Indianapolis. Indiana was admitted to the United States as the 19th s ...
(13), Illinois
Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. Its largest metropolitan areas include the Chicago metropolitan area, and the Metro East section, of Greater St. Louis. Other smaller metropolita ...
(9), Missouri
Missouri is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. Ranking List of U.S. states and territories by area, 21st in land area, it is bordered by eight states (tied for the most with Tennessee ...
and Oklahoma
Oklahoma (; Choctaw language, Choctaw: ; chr, ᎣᎧᎳᎰᎹ, ''Okalahoma'' ) is a U.S. state, state in the South Central United States, South Central region of the United States, bordered by Texas on the south and west, Kansas on the nor ...
(6), Ohio
Ohio () is a state in the Midwestern region of the United States. Of the fifty U.S. states, it is the 34th-largest by area, and with a population of nearly 11.8 million, is the seventh-most populous and tenth-most densely populated. The sta ...
(4), Alabama
(We dare defend our rights)
, anthem = "Alabama (state song), Alabama"
, image_map = Alabama in United States.svg
, seat = Montgomery, Alabama, Montgomery
, LargestCity = Huntsville, Alabama, Huntsville
, LargestCounty = Baldwin County, Al ...
and Tennessee
Tennessee ( , ), officially the State of Tennessee, is a landlocked state in the Southeastern region of the United States. Tennessee is the 36th-largest by area and the 15th-most populous of the 50 states. It is bordered by Kentucky to th ...
(3), and Florida
Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...
and Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the ...
(1).
Over 39 percent of all tornado-related deaths and many injuries come from residents of mobile home
A mobile home (also known as a house trailer, park home, trailer, or trailer home) is a prefabricated structure, built in a factory on a permanently attached chassis before being transported to site (either by being towed or on a trailer). Us ...
s. It is a widespread myth that tornadoes are "attracted" to mobile home parks, and cause the most fatalities there because they hit there the most. This is not true. However, mobile homes do often have poor construction and do not provide adequate protection during a tornado event. An example to confirm this occurred in April 1991, when a very powerful tornado struck the town of Andover, Kansas
Andover is a city in Butler County, Kansas, United States, and a suburb of Wichita. As of the 2020 census, the population of the city was 14,892. Andover is the most populated city in Butler County.
History
19th century
When the Kansas te ...
. When the town was hit, eighty-four homes and fourteen businesses were destroyed by the tornado, but with no fatalities and only minor injuries. After the tornado hit Andover, it swept through a mobile home park consisting of 223 trailers. The park did have a tornado shelter, to which over 200 residents fled and survived without injuries. Others that did not take shelter in the tornado shelter stayed in their mobile homes, and thirteen of them were killed by the tornado.
Damages
The Enhanced Fujita Scale
The Enhanced Fujita scale (abbreviated as EF-Scale) rates tornado intensity based on the severity of the damage they cause. It is used in some countries, including the United States, Canada, China, and Mongolia.
The Enhanced Fujita scale repla ...
classifies tornado strength from weakest - an EF0 tornado - to strongest - an EF5 tornado - based on damage caused to property and infrastructure.
An EF0 tornado has estimated wind speeds from which usually results in minor structural damage and broken tree limbs.
An EF5 tornado has estimated wind speeds of greater than and can destroy reinforced concrete structures and well-built homes, reducing them to piles of rubble or sweeping them entirely off their foundations or slabs.
When a tornado cannot be rated because there is no evidence that it caused structural or other relevant damage (which often occurs when a tornado touches down in unpopulated rural areas), it is classified as an EFU - U meaning "unknown" - tornado.
Forecasting
Until recently there was little hope of forecasting these systems. Meteorologists could identify those conditions that were likely to produce severe weather and generate a watch. If a tornado was spotted a warning was issued.
More recently Doppler radar allows investigators to see a circulation develop in the storm. Because of their size and intensity, there are
few storm observations. Increasing information has been gathered in the field from those chasing the storm.
Research activities
See also
*Tornado climatology
Tornadoes have been recorded on all continents except Antarctica. They are most common in the middle latitudes where conditions are often favorable for convective storm development. The United States has the most tornadoes of any country, as we ...
*List of North American tornadoes and tornado outbreaks
These are some notable tornadoes, tornado outbreaks, and tornado outbreak sequences that have occurred in North America.
#''The listing is U.S.-centric, with greater and more consistent information available for U.S. tornadoes. Some North Americ ...
*List of F5 and EF5 tornadoes
This is a list of tornadoes which have been officially or unofficially labeled as F5, EF5, T10-T11, IF5, or an equivalent rating, the highest possible ratings on the various tornado intensity scales. These scales – the Fujita scale, the Enhance ...
*Climate of the United States
The climate of the United States varies due to changes in latitude, and a range of geographic features, including mountains and deserts. Generally, on the mainland, the climate of the U.S. becomes warmer the further south one travels, and dri ...
Notes
Bibliography
*
*
*
External links
NOAA severe weather page
Electronic Journal of Severe Storms Meteorology
(National Geographic Magazine
''National Geographic'' (formerly the ''National Geographic Magazine'', sometimes branded as NAT GEO) is a popular American monthly magazine published by National Geographic Partners. Known for its photojournalism, it is one of the most widely ...
)
National Wind Institute at Texas Tech University
{{World topic, Tornadoes in, noredlinks=yes
Climate of the United States