You've probably heard this word numerous times since Monday, but what exactly is a 'Derecho?' How often do they occur?

According to the National Weather Service in Des Moines:

A derecho is a 250+ mile swath of wind damage, includes wind gusts of at least 58 mph along most of its length, and several, well-separated 75 mph or greater gusts.

Monday's Derecho traveled 770 miles in 14 hours across the Midwest. (See below)

According to NOAA, the word was first used in 1888 by Dr. Gustavus Hinrichs, a professor of physics at the University of Iowa.

In the USA are most common in the late spring and summer, with more than 75% occurring between April and August.

Most of Iowa will see a Derecho nearly once every two years. Far Eastern Iowa may see one every summer, as illustrated in the graph below:

Credit: NOAA