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On This Day in 1925, the U.S. Suffered Its Worst Tornado in History

March 18, 2020

March 18, 2020

Track of the Tri-State Tornado from 95 years ago, compared with GeoColor imagery of area today. Inset of TriState Tornado damage from historical photo.

On this day 95 years ago, the U.S.suffered its worst single-tornado in history—-the Tri-State Tornado. Producing more than 2.2 billion dollars in damage in today’s money, the tornado cut a path through the Midwest across the southern tip of Illinois, Missouri, and Indiana, and took nearly 700 lives. It lasted for over three hours, traveled 219 miles, and was reported by eyewitnesses to be a mile wide, a record width at the time.

The Enhanced Fujita scale, which is a set of wind estimates (not measurements) based on tornado damage, would consider the Tri-State Tornado to be the highest rating of EF5 due to the devastation it caused. Since there was no modern technology available at the time to record precise measurements from the storm, meteorologists used in-person surveying to assess the damage- “staying,” one account at the time explained, “as close to the storm track as the roads would permit.” Nowadays, satellite and radar information would be invaluable for local offices in those areas to issue live-saving tornado warnings to residents in case a similar situation would take place today.

Have you ever wondered why the United States sees so many tornadoes when other parts of the world do not experience the same amount? According to our meteorologists, it's due to the unique geography of the U.S. Great Plains. Also nicknamed “ Tornado Alley”, this expanse of flat land doesn’t provide a barrier between clashes of cold Canadian air and warm, moist air from the Gulf of Mexico. The Rockies to the west act as a funnel for this clash of air masses and help provide wind shear as jet stream winds blow over the peaks and across the Great Plains. All of these ingredients coming together can be a catalyst for severe storms and tornadoes.

The GOES-East geostationary satellite, also known as GOES-16, keeps watch over most of North America, including the continental United States and Mexico, as well as Central and South America, the Caribbean, and the Atlantic Ocean to the west coast of Africa. The satellite's high-resolution imagery provides optimal viewing of severe weather events, including thunderstorms, tropical storms, and hurricanes.