Illinois averaged 54 tornadoes per year based on 1991-2020 data.
A woman walks past downed tree limbs on her property along Main Street on April 1, 2023, in Belvidere. Tornado-strength winds on Friday swept through the area and damaged the Apollo Theatre on nearby State Street, whose roof and marquee sign collapsed during a concert, injuring at least 40 people and causing one fatality.
A tornado warning takes place when a tornado has already formed and been detected by radar or sighted by spotters. In this event, people in the designated area should seek shelter immediately. A tornado warning can be issued without a watch being issued first. Warnings are normally issued for about 30 minutes, according to the National Weather Service.
Nearly 60% of all tornadoes between 1950 and 2020 in Illinois occurred between 3 p.m. and 8 p.m. and most tornado-related injuries occurred between 2 and 5 p.m., according toTornadoesThey often develop from severe thunderstorms in warm, unstable air ahead of cold fronts. When warm and cool air combine in a storm, warm air rises and cool air falls. This vertical movement creates spin, which leads to the tornado’s funnel-like cloud.