On this day in 1925, the worst tornado in US history hit eastern Missouri, southern Illinois, and southern Indiana. It killed 695 people, injured another 13,000, and caused 17 million dollars in property damage.

I Think I'll Call It Tri-State. The terrible twister, which became known as the Tri-State Tornado, started in Ellington, Missouri, though southern Illinois was the hardest hit.

Up There. In the Sky. It's a Bird. It's a Plane. It's... A tornado is a dark, funnel-shaped cloud that contains violently rotating air. Tornadoes develop in climate conditions that, in the United States, tend to be unique to the central and southern plains and the Gulf states.

How Big? How Fast? The rotating winds of tornadoes can reach speeds of 300 miles per hour. Diameter ~ distance across the tornado ~ varies from a few feet to a mile. Tornadoes generally travel northeast at speeds of 20-40 mph, and cover between one and 100 miles.

In a Mere 3-1/2 Hours the Tri-State Tornado:

• traveled 219 miles
• wiped out 164 square miles
• had a diameter of over a mile
• traveled at speeds of more than 70 mph

Book of Records.

• longest continuous track on the ground: 219 miles
  
• third fastest traveling speed
  
• a record 3-1/2 hours in duration