Tri-State Tornado

Tri-State Tornado Outbreak

Newspaper coverage of the tornado
Type	Tornado outbreak
Duration	Wednesday, March 18, 1925
Tornadoes confirmed	12 known
Max rating1	F5 tornado
Duration of tornado outbreak2	7 hours
Largest hail	4.5 inches (11 cm) at Lexington, KY at 7:15 pm CST
Damage	>$1.4 billion (1997 USD) (Tri-State Tornado only)
Casualties	747+ (695+ from one tornado) fatalities, >2,298 injuries
Areas affected	Midwestern and Southeastern US
1Most severe tornado damage; see Fujita scale 2Time from first tornado to last tornado

¹Most severe tornado damage; see Fujita scale

The Tri-State Tornado of Wednesday, March 18, 1925 was the deadliest tornado in U.S. history. It was also the most exceptional tornado of a major outbreak of at least twelve known significant tornadoes across a large portion of the Midwestern and Southern U.S. It alone inflicted 695 fatalities, more than twice as many as the second deadliest, the Great Natchez Tornado of 1840. The 151 to 235 mi (243 to 378 km) track left by the tornado was the longest ever recorded in the world as it crossed from southeastern Missouri, through southern Illinois, then into southwestern Indiana. Although not officially rated by NOAA, it is recognized by most experts (such as Tom Grazulis and Ted Fujita) as an F5 tornado, the maximum damage rating issued on the Fujita scale.

The tornado was part of a larger tornado outbreak with several other destructive tornadoes the same day in Tennessee, Kentucky, and Indiana, as well as significant tornadoes in Alabama and Kansas. Including additional tornadoes that day, at least 747 people were killed and more than 2,298 were injured. This makes the Tri-State Outbreak the deadliest tornado outbreak, March 18 the deadliest tornado day, and 1925 the deadliest tornado year in U.S. history. There were undoubtedly other less impactful tornadoes, the occurrences of which have been lost to history.

It was a widespread outbreak with severe thunderstorms occurring as far east as Ohio, as far southwest as Louisiana and as far southeast as Georgia. Strong thunderstorms were reported in a broad area that also included parts of Oklahoma, Michigan, Ontario, Pennsylvania, and West Virginia. Numerous reports of hail and straight-line wind were reported with up to 4.5 in (11 cm) diameter hail recorded (for reference, a softball is 3.5–3.8 in (8.9–9.7 cm) in diameter). What began in early-mid afternoon as discrete supercell thunderstorms eventually consolidated into a potent squall line.