In the evening hours of June 17, 2010, a large and powerful multi-vortex tornado moved across

Freeborn County Freeborn County is a County (United States), county in the U.S. state, state of Minnesota. As of the 2020 United States census, 2020 census, the population was 30,895. Its county seat is Albert Lea, Minnesota, Albert Lea. Freeborn County compri ...

, located in the state of

Minnesota Minnesota ( ) is a U.S. state, state in the Upper Midwestern region of the United States. It is bordered by the Canadian provinces of Manitoba and Ontario to the north and east and by the U.S. states of Wisconsin to the east, Iowa to the so ...

. The tornado destroyed several buildings and farmsteads; one person was killed with fourteen others sustaining injuries to varying degrees. The tornado was one of four EF4-rated tornadoes to touch down on June 17, all of which occurred as part of the

June 2010 Northern Plains tornado outbreak The June 2010 Northern Plains tornado outbreak was one of the most prolific summer tornado outbreaks in the Northern Great Plains of the United States on record. The outbreak began on June 16, with several tornadoes in South Dakota and Montana. ...

. The tornado first touched down near

Mansfield Mansfield is a market town and the administrative centre of the Mansfield District in Nottinghamshire, England. It is the largest town in the wider Mansfield Urban Area and the second largest settlement in Nottinghamshire (following the city ...

, moving in an easterly direction as it moved north of

Conger ''Conger'' ( ) is a genus of marine congrid eels. It includes some of the largest types of eels, ranging up to or more in length, in the case of the European conger. Large congers have often been observed by divers during the day in parts of t ...

. The tornado then moved through areas near

Manchester Manchester () is a city and the metropolitan borough of Greater Manchester, England. It had an estimated population of in . Greater Manchester is the third-most populous metropolitan area in the United Kingdom, with a population of 2.92&nbs ...

, before dissipating several minutes later. The tornado was on the ground for , and received an EF4 rating after a damage survey was conducted.

Meteorological synopsis

On June 16, 2010, an upper-level

area of low pressure In meteorology, a low-pressure area (LPA), low area or low is a region where the atmospheric pressure is lower than that of surrounding locations. It is the opposite of a high-pressure area. Low-pressure areas are commonly associated with inclem ...

and associated

trough Trough may refer to: In science * Trough (geology), a long depression less steep than a trench * Trough (meteorology), an elongated region of low atmospheric pressure * Trough (physics), the lowest point on a wave * Trough level (medicine), the l ...

moved southeastward across 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 great-circle distance, straight-line distance from the northernmost part of Western Can ...

into the

Great Plains The Great Plains is a broad expanse of plain, flatland in North America. The region stretches east of the Rocky Mountains, much of it covered in prairie, steppe, and grassland. They are the western part of the Interior Plains, which include th ...

. Along the base of the trough, the presence of a strong mid-level

jet stream Jet streams are fast flowing, narrow thermal wind, air currents in the Earth's Atmosphere of Earth, atmosphere. The main jet streams are located near the altitude of the tropopause and are westerly winds, flowing west to east around the gl ...

provided significant instability; however, warm-air aloft was expected to limit the extent of

convective Convection is single or multiphase fluid flow that occurs spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convec ...

development. Moderate to strong deep layer

wind shear Wind shear (; also written 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 ...

along with steep lapse rates would allow for the development of

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 (su ...

thunderstorms with large

hail Hail is a form of solid Precipitation (meteorology), precipitation. It is distinct from ice pellets (American English "sleet"), though the two are often confused. It consists of balls or irregular lumps of ice, each of which is called a hailsto ...

(greater than in diameter). In light of this, the

Storm Prediction Center The Storm Prediction Center (SPC) is a US government agency that is part of the National Centers for Environmental Prediction (NCEP), operating under the control of the National Weather Service (NWS), which in turn is part of the National Oceani ...

issued a slight-risk of

severe weather Severe weather is any dangerous meteorological phenomenon with the potential to cause damage, serious social disruption, or loss of human life. These vary depending on the latitude, altitude, topography, and atmospheric conditions. High ...

for portions of

Colorado Colorado is a U.S. state, state in the Western United States. It is one of the Mountain states, sharing the Four Corners region with Arizona, New Mexico, and Utah. It is also bordered by Wyoming to the north, Nebraska to the northeast, Kansas ...

Montana Montana ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States. It is bordered by Idaho to the west, North Dakota to the east, South Dakota to the southeast, Wyoming to the south, an ...

Nebraska Nebraska ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders South Dakota to the north; Iowa to the east and Missouri to the southeast, both across the Missouri River; Ka ...

North Dakota North Dakota ( ) is a U.S. state in the Upper Midwest, named after the indigenous Dakota people, Dakota and Sioux peoples. It is bordered by the Canadian provinces of Saskatchewan and Manitoba to the north and by the U.S. states of Minneso ...

South Dakota South Dakota (; Sioux language, Sioux: , ) is a U.S. state, 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 Dakota people, Dakota Sioux ...

and

Wyoming Wyoming ( ) is a landlocked U.S. state, state in the Mountain states, Mountain West subregion of the Western United States, Western United States. It borders Montana to the north and northwest, South Dakota and Nebraska to the east, Idaho t ...

. The Storm Prediction Center issued a moderate risk of severe weather for June 17, 2010, citing a 10% threat for tornadoes, 45% threat for large hail and 45% threat for damaging wind, initially thinking tornadoes would quickly reform into a straight-line wind event. The moderate risk area extended from around

Fargo, North Dakota Fargo is the List of cities in North Dakota, most populous city in the U.S. state of North Dakota and the county seat of Cass County, North Dakota, Cass County. The population was 125,990 at the 2020 United States census, 2020 census, which was e ...

, to

Des Moines, Iowa Des Moines is the List of capitals in the United States, capital and List of cities in Iowa, most populous city in the U.S. state of Iowa. It is the county seat of Polk County, Iowa, Polk County with parts extending into Warren County, Iowa, Wa ...

, and

Omaha, Nebraska Omaha ( ) is the List of cities in Nebraska, most populous city in the U.S. state of Nebraska. It is located in the Midwestern United States along the Missouri River, about north of the mouth of the Platte River. The nation's List of United S ...

, including the

Twin Cities Twin cities are a special case of two neighboring cities or urban centres that grow into a single conurbation – or narrowly separated urban areas – over time. There are no formal criteria, but twin cities are generally comparable in stat ...

area, with a slight risk area extending across the

Upper Midwest The Upper Midwest is a northern subregion of the U.S. Census Bureau's Midwestern United States. Although the exact boundaries are not uniformly agreed upon, the region is usually defined to include the states of Iowa, Michigan, Minnesota and Wi ...

. Surface dew points reached the low 70s °F (low 20s °C) with surface temperatures well into 80s °F (near 30 °C) across Minnesota. Surface-based CAPE values were forecast to reach 2000–3000 J/kg. The first tornadoes were reported across eastern North Dakota during the mid-afternoon hours where a tornado watch was issued for most of the state as well as extreme northwestern Minnesota closer to the

Manitoba Manitoba is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population ...

and northwestern

Ontario Ontario is the southernmost Provinces and territories of Canada, province of Canada. Located in Central Canada, Ontario is the Population of Canada by province and territory, country's most populous province. As of the 2021 Canadian census, it ...

borders where many tornadoes, some strong to violent, touched down late that afternoon. After several tornadoes affected areas near the

Grand Forks Grand Forks is a city in and the county seat of Grand Forks County, North Dakota, United States. The city's population was 59,166 as of the 2020 census, making it the third-most populous city in the state, after Fargo and Bismarck. Grand For ...

area and closer to the Canada–US border, the activity eventually shifted into northwestern Minnesota by the late afternoon hours while storms over northern Iowa moved across southern Minnesota near the

Interstate 90 Interstate 90 (I-90) is an east–west transcontinental freeway and the longest Interstate Highway in the United States at . It begins in Seattle, Washington, and travels through the Pacific Northwest, Mountain states, Mountain West, Great Pla ...

corridor producing many tornadoes. Other storms developed over central Minnesota near

Interstate 94 Interstate 94 (I-94) is an east–west Interstate Highway connecting the Great Lakes and northern Great Plains regions of the United States. Its western terminus is just east of Billings, Montana, at a junction with I-90; its eastern ter ...

but most activity missed the Twin Cities area. The supercells eventually reached the Wisconsin border later that evening and reformed into a

squall line A squall line, or quasi-linear convective system (QLCS), is a line of thunderstorms, often forming along or ahead of a cold front. In the early 20th century, the term was used as a synonym for cold front (which often are accompanied by abrupt a ...

, rapidly ending the severe weather outbreak. Isolated tornado reports also occurred across Wisconsin and Iowa. One of the tornadoes produced by these supercells was the Conger–Albert Lea tornado.

Tornado summary

At 6:30 pm CDT, the tornado developed at the intersection of 610th Avenue and 60th Street, located near Mansfield. As the tornado moved to the northeast, it snapped power poles and trees, including a row of poles on County Road 11, which sustained EF1 damage. Swaths of trees in the area were also damaged, with some being snapped and others having heavy branch damage. Around this time, the tornado rapidly widened, reaching a width of as it produced EF2 damage for the first time. Rows of corn were flattened by the tornado as it continued to move to the northeast, and a home sustained roof damage. Around this time, a car was flipped and the tornado debarked several trees. The tornado continued to move to the northeast, carving a path through Freeborn County and producing intense crop damage. As the tornado reached , it began to damage structures at EF3 intensity, including to a farmstead that was heavily damaged. Several grain bins located nearby were also damaged, and a

wind turbine A wind turbine is a device that wind power, converts the kinetic energy of wind into electrical energy. , hundreds of thousands of list of most powerful wind turbines, large turbines, in installations known as wind farms, were generating over ...

was knocked over. Several more farmsteads were hit further northeast, and sustained EF3-rated damage. The tornado continued to the northeast across County Road 4, where field raking was documented and several trees were ripped out of the ground. Near County Road 89, the tornado turned to the north, growing to and reached EF4 intensity. A farmstead located two miles north of Conger was obliterated, and several nearby structures were also heavily damaged. A car that was thrown away, and heavy tree debarking was documented. The tornado then began to weaken, striking metal buildings at EF3 intensity, while a satellite tornado formed nearby, moving through the town of Armstrong. As the main tornado crossed County Road 74, it hit a farmstead at EF2 intensity, killing a woman who was sheltering inside and another west of Albert Lea. The tornado crossed Interstate 90, reaching EF3 intensity as it destroyed several farmsteads and damaged homes. The tornado then moved along a northward path, and the tornado destroyed more buildings as it passed west of

. Heavy tree damage was documented in this area, and other structural damage was found during a post-event damage survey conducted by the

National Weather Service The National Weather Service (NWS) is an Government agency, agency of the Federal government of the United States, United States federal government that is tasked with providing weather forecasts, warnings of hazardous weather, and other weathe ...

. A mile north, the tornado weaked and damaged several grain bins at EF2 intensity near County Road 29. The tornado was at this point in its life, and the tornado continued to weaken past this point. A farmstead sustained EF1 damage as the tornado moved past, and the tornado dissipated several minutes later, at 7:15 pm.

Aftermath

One person, Kathy Woodside, was killed by the tornado, and fourteen others were sent to nearby hospitals for their injuries. The tornado knocked power out for some time.

Notes and references

References

Sources