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 U.S. states were holding primary elections and caucuses to select the presidential candidates for the upcoming presidential election. Missouri, Illinois, Arkansas, Alabama, and Tennessee were among the affected regions in which primaries were being held. Some voting locations were forced to close early due to the approaching severe weather.
Eighty-seven tornadoes occurred over the course of the outbreak, which lasted over 15 hours from the afternoon of February 5 until the early morning of February 6. The storm system produced several destructive tornadoes in heavily populated areas, most notably in the Memphis metropolitan area, in Jackson, Tennessee, and the northeastern end of the Nashville metropolitan area.
A total of 57 people were killed across four states and 18 counties, with hundreds of others injured. The outbreak, at the time, was the deadliest in the era of modern NEXRAD doppler radar, which was fully implemented in 1997. The event was the second deadliest in February since 1950 behind the February 1971 Mississippi Valley tornado outbreak, which killed 123, the deadliest outbreak in both Tennessee and Kentucky since the 1974 Super Outbreak, and was at the time the deadliest tornado outbreak in the US overall since the 1985 United States–Canada tornado outbreak which killed 90 people. This record would not be surpassed until the 2011 Super Outbreak which killed 324 people. Damage from tornadoes was estimated at over $500 million (2008 USD).
The weather system which produced the tornadoes caused significant straight-line wind damage, hail as large as softballs – 4.5 inches (11 cm) in diameter – major flooding, significant freezing rain, and heavy snow across many areas of eastern North America. The total damage from the entire weather system exceeded $1 billion.