What is a Derecho? Vast Midwest Storm Threatens 1 in 5 Americans

Meteorologists are reporting that current weather conditions are favorable to the development of at least one Derecho this week. The Derecho storm would be so vast that it would affect 1-in-5 Americans with hail, lighting, and severe winds. 

Derecho windstorms, which occur about once every year, are long-lived lines of severe thunderstorms that produce high winds between 75 and 100 mph across distances in the hundreds of miles. They often occur across the central and northeastern U.S., where they bring heavy winds, and the possibility of tornadoes and heavy hail. The main risks are power outages and wind damage – such as downed trees, damaged roofs, etc – and are often accompanied by significant travel delays.

The major metropolitan areas that could be affected are Chicago, Indianapolis, Cincinnati and Columbus, where the risk of severe weather is 45 times above normal. Outside that area, the weather service is reporting that the likelihood of severe weather is 30% from Milwaukee to Pittsburgh, with a 15% chance of reaching the Washington, D.C., area.

Last year's Derecho caused over $1 billion in damaged from Chicago to Washington, killing 13 and knocking out the power of 4 million Americans. There is, however, no guarantee that Derecho-level storm will develop.