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 killed and more than 2,298 were injured, making the outbreak the deadliest tornado outbreak, March 18 the deadliest tornado day, and 1925 the deadliest tornado year in U.S. history. The outbreak generated several destructive tornadoes in Missouri, Illinois, and Indiana on the same day, as well as significant tornadoes in Alabama and Kansas. In addition to confirmed tornadoes, there were undoubtedly others with lesser impacts, the occurrences of which have been lost to history.
These are some notable tornadoes, tornado outbreaks, and tornado outbreak sequences that have occurred around the globe.
- Exact death and injury counts are not possible; especially for large events and events before 1955.
- Prior to 1950 in the United States, only significant tornadoes are listed for the number of tornadoes in outbreaks.
- Due to increasing detection, particularly in the U.S., numbers of counted tornadoes have increased markedly in recent decades although the number of actual tornadoes and counted significant tornadoes has not. In older events, the number of tornadoes officially counted is likely underestimated.
On April 10–12, 1965, a historic severe weather event affected the Midwestern and Southeastern United States. The tornado outbreak produced 55 confirmed tornadoes in one day and 16 hours. The worst part of the outbreak occurred during the afternoon hours of April 11 into the overnight hours going into April 12. The second-largest tornado outbreak on record at the time, this deadly series of tornadoes, which became known as the 1965 Palm Sunday tornado outbreak, inflicted a swath of destruction from Cedar County, Iowa, to Cuyahoga County, Ohio, and a swath 450 miles long (724 km) from Kent County, Michigan, to Montgomery County, Indiana. The main part of the outbreak lasted 16 hours and 35 minutes and is among the most intense outbreaks, in terms of tornado strength, ever recorded, including at least four "double/twin funnel" tornadoes. In all, the outbreak killed 266 people, injured 3,662 others, and caused $1.217 billion in damage. In 2023, tornado expert Thomas P. Grazulis created the outbreak intensity score (OIS) as a way to rank various tornado outbreaks. The 1965 Palm Sunday tornado outbreak received an OIS of 238, making it the fourth worst tornado outbreak in recorded history.
This article lists various tornado records. The most "extreme" tornado in recorded history was the Tri-State tornado, which spread through parts of Missouri, Illinois, and Indiana on March 18, 1925. It is considered an F5 on the Fujita Scale, holds records for longest path length at 219 miles (352 km) and longest duration at about 3+1⁄2 hours, and held the fastest forward speed for a significant tornado at 73 mph (117 km/h) anywhere on Earth until 2021. In addition, it is the deadliest single tornado in United States history with 695 fatalities. It was also the second costliest tornado in history at the time, and when costs are normalized for wealth and inflation, it still ranks third today.
A tornado outbreak is the occurrence of multiple tornadoes spawned by the same synoptic scale weather system. The number of tornadoes required to qualify as an outbreak typically are at least six to ten, with at least two rotational locations or at least two supercells producing multiple tornadoes.
There is a long history of destructive tornadoes in the St. Louis metropolitan area. The third-deadliest, and the costliest in United States history, the 1896 St. Louis–East St. Louis tornado, injured more than one thousand people and caused at least 255 fatalities in the City of St. Louis and in East St. Louis. The second-costliest tornado also occurred in St. Louis in September 1927. More tornado fatalities occurred in St. Louis than any other city in the United States. Also noteworthy is that destructive tornadoes occur in winter and autumn, as well as the typical months of spring. Additionally, damaging tornadoes occur in the morning and late at night, as well as the more common late afternoon to early evening maximum period.
On Thursday, March 27, 1890, a major tornado outbreak struck the Middle Mississippi Valley. To this day, this outbreak is still one of the deadliest tornado events in United States history. At least 24 significant tornadoes, several of which were generated by cyclic supercells, were recorded to have spawned from this system, and at least 187 people were killed by tornadoes that day, including a devastating F4 tornado that struck Downtown Louisville, Kentucky, killing at least 115 people and injuring at least 200 others. Five other violent tornadoes occurred elsewhere, including a long-tracked F4 tornado family that crossed two states, killing 21 people and injuring 200, and two other F4s that killed 14 altogether. A pair of F3s near the Tennessee–Kentucky state line may have killed a combined 37 people.
On February 19–20, 1884, one of the largest and most widespread tornado outbreaks in American history occurred over the Southeastern United States, known as the Enigma tornado outbreak due to the uncertain number of total tornadoes and fatalities. Nonetheless, an inspection of newspaper reports and governmental studies published in the aftermath reveals successive, long-tracked tornado families striking Alabama, Georgia, Illinois, Indiana, Kentucky, Mississippi, North Carolina, South Carolina, Tennessee and Virginia, with an estimation of at least 51—and possibly 60 or more—tornadoes.
On April 23–25, 1908, a destructive tornado outbreak affected portions of the Midwestern and Southern United States, including the Great Plains. The outbreak produced at least 31 tornadoes in 13 states, with a total of at least 324 tornado-related deaths. Of these deaths, most were caused by three long-tracked, violent tornadoes—each rated F4 on the Fujita scale and considered to be a tornado family—that occurred on April 24. Most of the deaths were in rural areas, often consisted of African Americans, and consequently may have been undercounted. One of the tornadoes killed 143 people along its path, 73 of them in the U.S. state of Mississippi, making the tornado the third deadliest in Mississippi history, following the 1936 Tupelo F5, with 216 deaths, and the 1840 Natchez tornado, with 317 deaths.
On March 21–22, 1952, a severe tornado outbreak generated eight violent tornadoes across the Southern United States, causing 209 fatalities—50 of which occurred in a single tornado in Arkansas. In addition, this tornado outbreak is the second deadliest on record to ever affect the state of Tennessee, with 66 of the fatalities associated with this outbreak occurring in the state; this is only surpassed by the 90 fatalities from a tornado outbreak in 1909, and in terms of fatalities is well ahead of both the 1974 Super Outbreak and the Super Tuesday tornado outbreak, each of which generated 45 and 31 fatalities, respectively. The severe weather event also resulted in the fourth-largest number of tornado fatalities within a 24-hour period since 1950. To date this was considered the most destructive tornado outbreak in Arkansas on record.
On March 21–22, 1932, a deadly tornado outbreak struck the Midwestern and Southern United States. At least 38 tornadoes—including 27 deadly tornadoes and several long-lived tornado families—struck the Deep South, killing more than 330 people and injuring 2,141. Tornadoes affected areas from Mississippi north to Illinois and east to South Carolina, but Alabama was hardest hit, with 268 fatalities; the outbreak is considered to be the deadliest ever in Alabama, and among the worst ever in the United States, trailing only the Tri-State tornado outbreak in 1925, with 751 fatalities, and the Tupelo–Gainesville outbreak in 1936, with 454 fatalities. The 1932 outbreak is believed to have produced 10 violent tornadoes, eight of which occurred in Alabama alone.
On March 16–17, 1942, a deadly late-winter tornado outbreak struck a large area of the Central and Southern United States, killing 149 people and injuring at least 1,312. At least five states reported violent tornadoes, from Illinois and Indiana south to Mississippi, beginning with an F4 tornado in the morning in Illinois. Intense activity spread south to the Gulf Coast and north to the Michigan–Indiana border as the day went on. Seven violent tornadoes were reported, one of which was a powerful F5 in Illinois. A long-tracked F4 tornado family in Mississippi claimed 63 lives as well, becoming the deadliest event of the outbreak. Another long-lived F4 in Tennessee killed 15 more people, and a series of intense tornadoes caused 24 other deaths in Kentucky. The outbreak also produced 18 tornadoes that caused at least one death—ranking eighth on a list of similar events since 1880 by tornado researcher Thomas P. Grazulis.
On April 4–5, 1966, an outbreak of at least three tornadoes affected portions of Florida and North Carolina. It included a deadly pair of tornado families that struck the I-4 corridor in Central Florida from the Tampa Bay Area to Brevard County. At least two long-tracked tornadoes affected the region, each of which featured a path length in excess of 100 mi (160 km). The two tornadoes are officially listed as continuous events, but the tornadoes' damage paths did not cross the entire state, and downbursts may have been responsible for destruction near Lake Juliana and in the Kissimmee–Saint Cloud area. However, tornado and downburst damage combined was continuous from coast to coast.
A deadly tornado outbreak affected much of the central and Southern United States from April 29 – May 1, 1909. Affecting particularly the Mississippi and Tennessee Valleys, it killed over 180 people, more than 90 of them in the U.S. state of Tennessee alone. The deadliest and longest-tracked tornado of the outbreak was a violent F4 tornado family that tracked across portions of northern Mississippi and western Tennessee on April 29, claiming at least 29 lives. Another deadly F4 tornado struck portions of southern Tennessee early the next day, killing 31. Other F4s in southern Missouri and southern Illinois on April 29 killed a combined 16 people. Deadly F3s in Georgia and Tennessee from April 30–May 1 killed a total of at least 53 people as well.
The March 1875 Southeast tornado outbreak was a deadly tornado outbreak that affected portions of the Southern United States from March 19–20, 1875. At least 19 tornadoes were recorded, including seven that were destructive enough to be rated F4 by Thomas P. Grazulis. The worst damage and most of the deaths occurred in Georgia. Most of the damage appears to have been the result of two tornado families that moved along parallel paths 12 to 15 mi apart through parts of Georgia and South Carolina. These families each consisted of numerous long-tracked, intense tornadoes. The deadliest tornado of the outbreak was an estimated F4 that killed 28–42 people in and near Sparta, Georgia, and Edgefield, South Carolina, on March 20. A separate F4 that followed a similar trajectory may have killed as many as 30. In all, this outbreak killed at least 96 people, injured at least 377, and caused at least $650,000 in losses.
On April 18–20, 1880, a tornado outbreak impacted the Midwestern United States, producing numerous strong tornadoes, killing at least 166 people, and injuring more than 516 others. The outbreak generated five violent tornadoes, including three long-tracked F4 tornadoes in Missouri that killed at least 144 people. Two of the tornadoes followed parallel paths and occurred simultaneously near Springfield, one of which devastated the town of Marshfield, causing 92 fatalities there. Other deadly, intense tornadoes occurred in the Great Lakes region and in Arkansas, including another F4 tornado that destroyed a third of El Paso, Arkansas, killing four or more people.
On Thursday, September 29, 1927, an outbreak of at least 15 significant tornadoes, including three F3 tornadoes, killed at least 82 people in the Central United States, particularly in Missouri and Illinois. The outbreak affected a broad expanse of the Midwestern and Southern United States, including Oklahoma, Missouri, Arkansas, Iowa, Illinois, and Indiana. The deadliest tornado was an estimated F3 which affected portions of Greater St. Louis, killing at least 79 people and injuring at least 550 others. The tornado narrowly missed Downtown St. Louis, striking north of the central business district before crossing the Mississippi River.
Several destructive tornadoes struck the Southeastern United States, primarily along and east of the Lower Mississippi Valley, on February 13, 1952. Multiple intense tornadoes touched down throughout the day, three of which were killers. The deadliest and most destructive tornado of the outbreak was a violent F4 that touched down in south-central Tennessee, killing three people and injuring 44 others. A similarly destructive tornado—albeit of weaker, F2 intensity—formed from the same storm as the preceding F4 and became the second costliest of the outbreak. Another intense tornado affected the Mississippi embayment near Manila, Arkansas, injuring five people, and a pair of deadly F3s in Alabama claimed a combined two lives. In all, the outbreak killed five people and injured 102 others.
