Today Marks the One-Year Anniversary of the 2021 Historic December 15th Derecho

It's hard to believe that almost a year has passed (12/15) since the 2021 December Derecho struck the state of Iowa and adjacent states.  Check out this link to the event review webpage and below are as some facts from this unprecedented and historic event. 

• Event damage cost exceeded 1 billion dollars
• First ever derecho recorded anywhere in the United States during the month of December
• First moderate risk of severe thunderstorms ever issued by the Storm Prediction Center for Iowa during the month of December
• Most tornadoes recorded in Iowa on a single day - 63 (the previous record was 35 on the evening of 8/31/14)
• Accounted for over half of Iowa's 2021 tornado total of 114
• Most EF2/F2 or stronger tornadoes recorded in on Iowa on a single day - 21 (previous record was 16 on 6/7/84)
• Prior to this event a grand total of just 5 tornadoes occurred in Iowa in December since 1950 (all of them in southeast Iowa)
• Strongest non-thunderstorm wind gust (74 mph) observed in over 50 years at the Des Moines International Airport
• Breaks the all-time record high temperature for Iowa in December (75F in Oskaloosa, Muscatine, Iowa City, & Ottumwa).  Previous record was 74F in Thurman, IA on 12/6/39.
• Event tornado total (Nebraska, Iowa, Minnesota, and Wisconsin combined) - 120
• Highest thunderstorm wind gusts recorded was 88 mph in Audubon
• Highest tornado wind gusts recorded was 108 mph near Sheffield

Derecho FAQ's

What is a derecho?
A derecho is a widespread, long-lived wind storm associated with a band of rapidly moving showers and thunderstorms (squall line).  Although a derecho can produce destruction similar to a tornado, the damage typically occurs in one direction along a relatively straight swath (sometimes referred to as "straight-line wind damage").

How strong are derecho winds?
A derecho must include wind gusts of at least 58 mph or greater along most of its length.  

What is the criteria to be classified as a derecho?
A nearly continuous damage path over a swath of at least ~400 miles in length AND ~60 miles in width.

Where does the term DERECHO come from?
A Spanish word meaning "straight ahead" or "direct" coined in 1877 by Gustavus Hinrichs, University of Iowa physics professor. The term was created to discriminate in wind damage caused by tornadoes.

How often do DERECHOES impact Iowa?
On average, a derecho impacts a portion of Iowa every 1-2 years.

More Derecho Facts can be found on the Storm Prediction Center's Webpage HERE.

Interviews requests can be directed to the National Weather Service at nws.desmoines@noaa.gov or by phone at (515) 270-2614.