The Tornado outbreak sequence of March 18–24, 2012 was a long lasting tornado outbreak that occurred due to a slow moving, but powerful

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 ...

and cutoff low. The outbreak began in 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 ...

, where, over a two-day period, several tornadoes touched down, some of which were significant. The North Platte area was damaged by an EF3 that was produced by a supercell that spawned many tornadoes throughout its lifespan. The tornadic activity then shifted the Southern United States over subsequent days, particularly in

Louisiana Louisiana ( ; ; ) is a state in the Deep South and South Central regions of the United States. It borders Texas to the west, Arkansas to the north, and Mississippi to the east. Of the 50 U.S. states, it ranks 31st in area and 25 ...

and

Mississippi Mississippi ( ) is a U.S. state, state in the Southeastern United States, Southeastern and Deep South regions of the United States. It borders Tennessee to the north, Alabama to the east, the Gulf of Mexico to the south, Louisiana to the s ...

. These states were struck by a series of tornadoes for 3 days, most of which were relatively weak on the

Enhanced Fujita Scale The Enhanced Fujita scale (abbreviated EF-Scale) is a scale that rates tornado intensity based on the severity of the damage a tornado causes. It is used in the United States and France, among other countries. The EF scale is also unofficially ...

. However, a few reached EF2 intensity and caused considerable damage. Tornado activity continued across the

Ohio Valley The Ohio River () is a river in the United States. It is located at the boundary of the Midwestern and Southern United States, flowing in a southwesterly direction from Pittsburgh, Pennsylvania, to its mouth on the Mississippi River in Cairo, ...

on the 23rd, with one confirmed fatality in southern Illinois.

Meteorological synopsis

March 18–19

March 20–22

March 23–24

A slight risk was issued for parts of the

, but notable tornado activity was not expected. However, several tornadoes touched down across Indiana, Illinois, Ohio, and Kentucky.

Supercell thunderstorms A supercell is a thunderstorm characterized by the presence of a mesocyclone, a deep, persistently rotating vertical draft, updraft. Due to this, these storms are sometimes referred to as rotating thunderstorms. Of the four classifications of th ...

developed and produced large hail as well. One high-end EF1 tornado caused considerable damage to homes in the

Louisville Louisville is the most populous city in the Commonwealth of Kentucky, sixth-most populous city in the Southeast, and the 27th-most-populous city in the United States. By land area, it is the country's 24th-largest city; however, by populatio ...

metro area. An EF2 tornado caused one fatality in southern

Illinois Illinois ( ) is a U.S. state, state in the Midwestern United States, Midwestern United States. It borders on Lake Michigan to its northeast, the Mississippi River to its west, and the Wabash River, Wabash and Ohio River, Ohio rivers to its ...

when a mobile home was thrown and completely destroyed. On the 24th, an isolated EF0 touched down in

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

as the outbreak moved eastward and came to an end.

Confirmed tornadoes

March 18 event

March 19 event

March 20 event

March 21 event

March 22 event

March 23 event

March 24 event

References

{{DEFAULTSORT:2012-03-18 tornado outbreak sequence 03-18 Tornadoes in Louisiana Tornadoes in Mississippi Tornadoes in Nebraska Tornado,2012-03-18

Tornado A tornado is a violently rotating column of air that is in contact with the surface of 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, although the ...