Havoc in the Midwest Was Caused by a Rare December Derecho Windstorm

(Bloomberg) -- Last week’s wave of thunderstorms and tornadoes that killed at least five after sweeping out of Nebraska and Kansas across the Midwest was a serial derecho, according to the National Weather Service.

Unusual for this time of year, a serial derecho shows up as a series of bow-like arcs of storms and winds embedded in a larger weather system that can cause destructive and dangerous conditions. Last week’s storm blasted winds up to 97 miles (156 kilometers) per hour across Nebraska and tornadoes were reported in Minnesota, while the storm set a record for the number of 75 mph winds or higher recorded across the central U.S., the Storm Prediction Center said. 

While destructive, last week’s derecho didn’t rise to the level of one in August 2020 that knocked out power to 1 million customers and ripped an $11 billion path of carnage across the Midwest in just a few hours, according to a tweet from the National Weather Service in Des Moines. 

The name derived from the Spanish in the 19th century to describe winds that were straight and not twisted as tornadoes are. Typically 70% of them form in May to August when temperatures soar and the air is humid, while only 1% tend to occur in December, the weather service said. 

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