On February 21–22, 1971, a devastating tornado outbreak, colloquially known as the Mississippi Delta outbreak, struck portions of the Lower Mississippi and Ohio River valleys in the Southern and Midwestern United States. The outbreak generated strong tornadoes from Texas to Ohio and North Carolina. The two-day severe weather episode produced at least 19 tornadoes, and probably several more, mostly brief events in rural areas; killed 123 people across three states; and wrecked entire communities in the state of Mississippi. The strongest tornado of the outbreak was an F5 that developed in Louisiana and crossed into Mississippi, killing 47 people, while the deadliest was an F4 that tracked across Mississippi and entered Tennessee, causing 58 fatalities in the former state. The former tornado remains the only F5 on record in Louisiana, while the latter is the deadliest on record in Mississippi since 1950. A deadly F4 also affected other parts of Mississippi, causing 13 more deaths. Other deadly tornadoes included a pair of F3s—one each in Mississippi and North Carolina, respectively—that collectively killed five people. Background At 12:00 UTC on February 21, 1971, surface weather analysis failed to indicate either a well-developed low-pressure area or a defined frontal boundary over the Gulf Coastal Plain, signs that would normally presage a severe weather outbreak. At the time, a diffuse warm front extended eastward from East Texas to portions of Mississippi, and a cold front extended southward over East Texas. Higher up in the atmosphere, conditions were "close to ideal" for a significant tornado outbreak: a broad trough imparted substantial divergence over the prefrontal warm sector. Impact Activity started early on the morning of February 21. The first tornadoes touched down in Texas east of Austin and north of Waco. The main activity intensified during the afternoon over the Mississippi and Tennessee Valleys until the late evening hours. At 15:55 UTC the National Severe Storms Forecast Center (NSSFC) in Kansas City, Missouri, issued a tornado watch for eastern Arkansas, northern Mississippi, and adjourning portions of Tennessee and Alabama. A subsequent watch covered portions of eastern Louisiana and southwestern Mississippi, more than an hour before the first major tornado developed. Three violent, long-lived tornadoes—two of which may have been tornado families—in western Mississippi and northeastern Louisiana caused most of the deaths along of path. The first of the three long-lived violent tornadoes was an F5 that touched down in Louisiana and traveled continuously for