The tornado outbreak sequence of May 2004 was a series of

tornado outbreak A tornado outbreak is the occurrence of multiple tornadoes spawned by the same Synoptic scale meteorology, synoptic scale weather system. The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least ...

s that affected much of southern

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 ...

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

, the Central and Southern United States from east of the Rockies to the

Mid-Atlantic States The Mid-Atlantic is a region of the United States located in the overlap between the nation's Northeastern and Southeastern states. Traditional definitions include seven U.S. states: New York, New Jersey, Pennsylvania, Delaware, Maryland, Virg ...

from May 21 to May 31, 2004. Particularly hard hit were the central Plains from

Missouri Missouri (''see #Etymology and pronunciation, pronunciation'') 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 border ...

Iowa Iowa ( ) is a U.S. state, state in the upper Midwestern United States, Midwestern region of the United States. It borders the Mississippi River to the east and the Missouri River and Big Sioux River to the west; Wisconsin to the northeast, Ill ...

and 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, ...

. The Central Plains were hit by two significant outbreaks on May 22 and May 24, the first outbreak of which produced a very large and violent F4 tornado in Hallam, Nebraska on May 22. The

was affected by one of the largest tornado outbreaks ever during the Memorial Day weekend on May 29–30. Seven people were killed in four states during the entire event. In all, 389 tornadoes were confirmed over an 11-day period – close to the number of tornadoes in the May 2003 tornado outbreak sequence which affected more or less the same area. However, the 2003 outbreak sequence produced several more destructive and violent tornadoes and had a much higher death toll than in May 2004.

Confirmed tornadoes

Hallam tornado outbreak

The Hallam, Nebraska tornado outbreak was an

outbreak In epidemiology, an outbreak is a sudden increase in occurrences of a disease when cases are in excess of normal expectancy for the location or season. It may affect a small and localized group or impact upon thousands of people across an entire ...

of 56

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 ...

es in several Midwestern U.S. states on the evening of May 22, 2004 and the first of a series of tornado events. Most of the tornadoes occurred in

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 ...

and

. On that day, a warm, moist airmass was sitting over Nebraska while an upper-level low developed in Colorado, with an attending dryline forming ahead of the advancing cold front. One person was killed in this outbreak, 38 were injured and there was $175 million in damage. The worst tornado was an F4 that struck Hallam, Nebraska. The violent tornado was ranked as one of the widest tornadoes on record, with the funnel stretching wide as it passed through Hallam. This record was surpassed on May 31, 2013, by an EF3 tornado in El Reno, Oklahoma that reached 2.6 miles wide.

Timeline

The first tornado in this outbreak touched down at 1:15 MDT near La Grange, Wyoming. It was an F0 and did not cause any significant damage. After another small tornado touched down in

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 ...

, several tornadoes began to form in Nebraska and Iowa during the mid–afternoon hours where they continued until around 11:00 p.m CDT. The most damaging tornado in the outbreak first touched down at 7:30 p.m. CDT in northwestern Jefferson County. The tornado then moved to the northeast, through southern Saline County and northwestern Gage County. By the time it entered Lancaster County, it measured an F4 on the

Fujita scale The Fujita scale (F-Scale; ), or Fujita–Pearson scale (FPP scale), is a scale for rating tornado intensity, based primarily on the damage tornadoes inflict on human-built structures and vegetation. The official Fujita scale category is determ ...

and the damage path was wide. The tornado passed into Otoe County, disappearing just west of

Palmyra Palmyra ( ; Palmyrene dialect, Palmyrene: (), romanized: ''Tadmor''; ) is an ancient city in central Syria. It is located in the eastern part of the Levant, and archaeological finds date back to the Neolithic period, and documents first menti ...

at 9:10. The tornado had a path length of about 54 miles, and was on the ground for 100 minutes.

Damage

The village of Hallam, struck at 8:33 p.m., was the hardest hit. Approximately 95% of the buildings in Hallam were damaged or destroyed. There were 37 people injured and one fatality in the village. The Norris School District 160 high school building was severely damaged; its auditorium was destroyed. Straight-line winds caused damage in

Princeton Princeton University is a private Ivy League research university in Princeton, New Jersey, United States. Founded in 1746 in Elizabeth as the College of New Jersey, Princeton is the fourth-oldest institution of higher education in the Unit ...

. Several farms and rural homes suffered extensive damage. This storm also derailed a freight train and left it lying 20 feet away from the railroad. Other significant damage occurred from an F2 tornado in Adams and

Clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

counties, Nebraska. Fifteen homes were damaged and another train was overturned, resulting in $5.5 million in damages.

Memorial Weekend outbreak

The 2004 Memorial Day Weekend tornado outbreak was the largest continuous tornado outbreak ever recorded in the month of May. It lasted for two days from May 29–30, 2004 with the final tornadoes occurring during the early morning hours of May 31. This

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 ...

and continued throughout the

Midwest The Midwestern United States (also referred to as the Midwest, the Heartland or the American Midwest) is one of the four census regions defined by the United States Census Bureau. It occupies the northern central part of the United States. It ...

. Tornadoes on the 29th were focused from the Dakotas to

and

Oklahoma Oklahoma ( ; Choctaw language, Choctaw: , ) is a landlocked U.S. state, state in the South Central United States, South Central region of the United States. It borders Texas to the south and west, Kansas to the north, Missouri to the northea ...

before shifting east to the

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 ...

Ohio Ohio ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Erie to the north, Pennsylvania to the east, West Virginia to the southeast, Kentucky to the southwest, Indiana to the ...

and

Tennessee Valley The Tennessee Valley is the drainage basin of the Tennessee River and is largely within the U.S. state of Tennessee. It stretches from southwest Kentucky to north Alabama and from northeast Mississippi to the mountains of Virginia and North C ...

s on the 30th. The official Storm Data archives fro
NOAA
list a total of 168 tornadoes during the two-day period. Unofficial storm reports compiled by 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 ...

indicated 199 tornadoes, but these reports are strictly preliminary and are not quality controlled to the degree of Storm Data publications. The 168 tornadoes occurred in 32 hours of continuous activity, which would not at all break the record held by the

1974 Super Outbreak The 1974 Super Outbreak was one of the most intense tornado outbreaks on record, occurring on April 3–4, 1974, across much of the United States. It was one of the deadliest tornado outbreaks in U.S. history. It was also the most violent t ...

, which saw 148 tornadoes in 18 hours. There was also a greater number of large and violent tornadoes in the Super Outbreak event. Most of the tornadoes were produced by supercells, though a few were produced by the following squall line. There were also widespread wind damage reports from a large

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 ...

that moved through after the tornadoes. Damage totals from this outbreak are at $62.321 million. The tornado outbreak killed at least 5 people across two states including 4 in

and 1 in

Indiana Indiana ( ) is a U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Lake Michigan to the northwest, Michigan to the north and northeast, Ohio to the east, the Ohio River and Kentucky to the s ...

. 3 of the fatalities were caused by an F4 tornado that struck the Weatherby area in

DeKalb County, Missouri DeKalb County is a county located in the northwest portion of the U.S. state of Missouri. As of the 2020 census, the population was 11,029. Its county seat is Maysville. The county was organized February 25, 1845 and named for General Johann ...

late during the evening of May 29. Another person was killed in the

St. Louis St. Louis ( , sometimes referred to as St. Louis City, Saint Louis or STL) is an independent city in the U.S. state of Missouri. It lies near the confluence of the Mississippi and the Missouri rivers. In 2020, the city proper had a populatio ...

Metropolitan area while the fifth fatality was northwest of

Louisville, Kentucky Louisville is the List of cities in Kentucky, most populous city in the Commonwealth of Kentucky, sixth-most populous city in the Southeastern United States, Southeast, and the list of United States cities by population, 27th-most-populous city ...

in the Marengo area where 80% of the town was damaged or destroyed. In addition, an F2 tornado on May 30 affected portions of the

Indianapolis Indianapolis ( ), colloquially known as Indy, is the List of capitals in the United States, capital and List of municipalities in Indiana, most populous city of the U.S. state of Indiana and the county seat of Marion County, Indiana, Marion ...

Metropolitan Area just a few hours after the

Indianapolis 500 The Indianapolis 500, formally known as the Indianapolis 500-Mile Race, and commonly shortened to Indy 500, is an annual automobile race held at the Indianapolis Motor Speedway in Speedway, Indiana, United States, an enclave suburb of Indian ...

was taking place. The tornado missed the

Indianapolis Motor Speedway The Indianapolis Motor Speedway is a motor racing circuit located in Speedway, Indiana, United States, an enclave suburb of Indianapolis, Indiana. It is the home of the Indianapolis 500 and the Brickyard 400, and and formerly the home of the U ...

by six miles and forced post-racing events to be held indoors. The tornado did however cause extensive damage across southern and eastern Marion County south of the downtown area. While 26 people were injured, over 700 structures were damaged by the storm.

Other outbreaks

Several other smaller tornado outbreaks took place between May 21 to May 31, 2004, and affected many of the regions impacted by the two main outbreaks. On May 21, a series of tornadoes hit Iowa causing major damage to the town of Bradgate where 75% of the buildings were either damaged or destroyed. On this day, several clusters of thunderstorms traveled from the Midwest to the Mid-Atlantic States producing widespread damaging wind and weaker tornadoes across

Michigan Michigan ( ) is a peninsular U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, Upper Midwestern United States. It shares water and land boundaries with Minnesota to the northwest, Wisconsin to the west, ...

. On May 24, several tornadoes touched down across the Great Plains and the Mid-Mississippi Valley. Most tornadoes were weak although one person was killed in Illinois inside a mobile home.Storm Prediction Center Storm Reports
/ref> On May 26–27, several tornadoes affected portions of the

. One tornado north of

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 ...

producing significant damage in Washington and Clark Counties. An F3 tornado tore through a residential subdivision just north of

Lexington, Kentucky Lexington is a Consolidated city-county, consolidated city coterminous with and the county seat of Fayette County, Kentucky, United States. As of the 2020 United States census, 2020 census the city's population was 322,570, making it the List of ...

causing major damage to about 50 homes.

References

External links

May 22

Hallam Nebraska Tornado
(NWS Omaha, Nebraska)
Summary of the Storms of May 22nd and 24th, 2004
(NWS Hastings, Nebraska)

(

University of Nebraska–Lincoln The University of Nebraska–Lincoln (Nebraska, NU, or UNL) is a Public university, public Land-grant university, land-grant research university in Lincoln, Nebraska, United States. Chartered in 1869 by the Nebraska Legislature as part of the M ...

)
22 May 2004 - Severe Convection in Nebraska and Iowa
(CIMSS, SSEC,

University of Wisconsin–Madison The University of Wisconsin–Madison (University of Wisconsin, Wisconsin, UW, UW–Madison, or simply Madison) is a public land-grant research university in Madison, Wisconsin, United States. It was founded in 1848 when Wisconsin achieved st ...

)

May 24

Storm images from May 24 tornadoes in Kansas and Nebraska

May 29–31

May 29, 2004: Tornadoes across Northwest Missouri
(NWS Kansas City, Missouri)
May 30, 2004 Tornado Outbreak
(NWS Indianapolis, Indiana)
F3 tornado strikes Peru, Indiana
(NWS Northern Indiana)
Severe Weather Outbreak of May 30, 2004
(NWS Central Illinois)
30 May 2004 Event
(NWS St. Louis)
Jefferson County, Kentucky Tornado Damage
(NWS Louisville, Kentucky)
Floyd County, Indiana Tornado Damage
(NWS Louisville, Kentucky)
Crawford County, Indiana (Marengo) Tornado Damage
(NWS Louisville, Kentucky)
Clark County, Indiana Tornado Damage
(NWS Louisville, Kentucky)
Tornadoes in the Paducah county warning area
(NWS Paducah, Kentucky) {{DEFAULTSORT:2004-05-22 Tornado Outbreak Sequence F4, EF4 and IF4 tornadoes 05-22 Tornadoes in Indiana Tornadoes in Illinois Tornadoes in Iowa Tornadoes in Kansas Tornadoes in Kentucky Tornadoes in Missouri Tornadoes in Nebraska Tornadoes in Oklahoma 2004-05-22 Tornado outbreaks in the United States Tornado, 05-22 Tornado, 22