A severe weather event developed across the Midwest and southern Great Plains on April 19 as a dynamic low pressure system tracked across the area. Thunderstorms began in the late afternoon and early evening with large hail and several tornadoes. Significant damage was reported near Bowling Green, Missouri and Girard, Illinois as a result of tornadoes, the latter of which was rated EF3. Another large tornado was reported near Octavia, Oklahoma before the supercells merged into a very large squall line. Overnight, the squall line tracked eastward with widespread wind damage and many embedded tornadoes across several states, a few as strong as EF2 but most were brief and weak. In the early hours of April 20, 2011, a tornado tore through a neighborhood in Oregon, Ohio leaving some significant damage and no injuries.
Severe weather once again developed across parts of the Midwest on April 22. The St. Louis metropolitan area was hit hardest by the storm system. An EF4 tornado tracked across the region. Severe effects occurred in several communities, including houses and other buildings destroyed in Bridgeton, Ferguson, Florissant, Hazelwood, Maryland Heights, New Melle, and other communities. The tornado caused extensive damage to numerous facilities at Lambert-St. Louis International Airport, with injuries reported; airplanes were damaged from the high winds and terminal windows blew out. American Airlines claimed four of their jets were damaged, two significantly. The airport was closed for days after the tornado. The EF4 tornado rating was based on finding of leveled houses in Bridgeton. Following assessments by the localNational Weather Service, it was determined that a single tornado tracked for 22 mi through parts of Missouri and Illinois. It reached a maximum width of 0.4 mi.Elsewhere, there were several reported tornadoes, including an EF2 which tracked through Henderson, Webster and Union County. Miraculously, there were no fatalities or serious injuries that resulted from this storm.
April 23–24
Scattered tornadoes were reported across the US, but most were weak or remained over open country. However one tornado caused EF2 damage in the town of Bardwell, Kentucky. Another EF2 tornado destroyed airplane hangars near Cairo, Illinois. These later tornadoes were not part of the same weather system as the earlier tornadoes; they were part of a weather system that led to the 2011 Super Outbreak.
