Showers, Flowers, and Tornadoes

Pat Guinan
State Climatologist
Commercial Agriculture/University of Missouri Extension

The clash of air masses occur over Missouri during spring, especially in April and May, as remnants of winter do not want to let go and summer heat is just around the corner. Thunderstorms are common during this transition season and, every once in a while, all the ingredients fall into place for severe thunderstorms that can bring flooding rains, damaging hail, and strong winds. Another more elusive ingredient that can be associated with severe thunderstorms, and also the most terrifying, is the tornado.

Missouri recorded a total of 91 tornadoes last year, the second highest on record since 1950. On average, the Show-Me state experiences just over 30 tornadoes a year with about 50% of them occurring during April and May. Tornadoes can occur any time of the year and any time of the day but a majority of them (83%) occur between noon and midnight.

Over the past 30 years, through the efforts of science and technology, we have uncovered a lot of the mystique that surrounds a tornado. Improvements have also been made in public awareness and safety procedures to minimize the effect that tornadoes can have on life and property.

One milestone that stressed the importance of school safety and debunked some tornado myths was the Super Outbreak of April 3-4, 1974. The Super Outbreak is the worst tornado outbreak in U.S. history. A total of 148 twisters touched down in 13 states killing 330 people and injuring over 5000. Damage surveys, eyewitness reports and pictures of this event provided evidence to disprove some myths about tornadoes.

Some myths that were untrue include:

Myth: A tornado will not strike at the confluence of major rivers. Fact: Cairo, IL, located where the Ohio and Mississippi Rivers merge, was struck by a tornado that day.

Myth: Tornadoes will not traverse steep or high hills. Fact: A tornado developed in the Blue Ridge mountains of north Georgia and climbed a 3,000 foot ridge before descending to the bottom of a canyon. Another tornado in Indiana descended a 60-foot bluff, crossed a river and damaged homes nestled in a valley.

Damage surveys of schools hit during the Super Outbreak provided information for engineers to revise construction designs that would be safer for students. Some of the school damage patterns proved claims that inside hallways away from glass are the safest place to be. Classrooms with outside walls, areas with windows, lunch rooms and gymnasiums are the most dangerous places for students during severe weather.

Most deaths and injuries from tornadoes are from flying debris. If you are in a house go to the lowest possible level and stay away from windows, doors, or outside walls. If a basement is not available, go to the interior portions of the lowest level. Get as many walls between you and the outdoors. Closets, bathrooms, and interior hallways offer the most protection.