1967 St. Louis tornado outbreak

An extremely rare wintertime tornado outbreak affected the Midwestern United States on January 24, 1967. Of the 30 confirmed tornadoes, 13 occurred in Iowa, nine in Missouri, seven in Illinois, and one in Wisconsin. The outbreak produced, at the time, the northernmost tornado to hit the United States in winter, in Wisconsin, until January 7, 2008. The tornadoes formed ahead of a deep storm system. The deadliest and most damaging tornado of the outbreak struck Greater St. Louis at F4 intensity, killing three people and injuring 216.

Background
On Tuesday, January 24, 1967, a negatively tilted trough bisected the Midwestern United States. As a cold front traversed the Upper Midwest, a line of intermittent, tornado-producing supercells developed.

Confirmed tornadoes
Prior to 1990, there is a likely undercount of tornadoes, particularly E/F0–1, with reports of weaker tornadoes becoming more common as population increased. A sharp increase in the annual average E/F0–1 count by approximately 200 tornadoes was noted upon the implementation of NEXRAD Doppler weather radar in 1990–1991. 1974 marked the first year where significant tornado (E/F2+) counts became homogenous with contemporary values, attributed to the consistent implementation of Fujita scale assessments. Numerous discrepancies on the details of tornadoes in this outbreak exist between sources. The total count of tornadoes and ratings differs from various agencies accordingly. The list below documents information from the most contemporary official sources alongside assessments from tornado historian Thomas P. Grazulis.


 * Along with the 30 confirmed tornadoes listed, tornado researcher Thomas P. Grazulis listed two additional F2 tornadoes that may have touched down.
 * The first occurred west of Muscatine, Muscatine County, Iowa, at 22:30 UTC, unroofing and tearing apart a house. It was officially listed as a severe thunderstorm wind in Storm Data.
 * The other occurred on the southern outskirts of Illinois City, Rock Island County, Illinois, at an unknown time, damaging homes before ripping the roof off a farmhouse. It was officially listed as part of a complex of severe thunderstorm winds in Storm Data.

Northern Chesterfield–Maryland Heights–St. Ann–Lambert Field–Spanish Lake, Missouri
Tornado moved through the St. Louis suburbs striking Maryland Heights, St.Ann, Lambert Field, and Spanish Lake. 168 homes were destroyed and 1740 others were damaged. Some of the homes were leveled. A nursing home was also badly damaged.