A derecho with at least one 99 mph gust swept the Upper Plains and Midwest, the weather service says

Strong storms that brought hurricane-force winds to an area stretching from the Upper Plains to the Midwest have been preliminarily classified by the National Weather Service as a derecho, defined as a long-lived line of storms with extreme winds.

The weather service's Storm Prediction Center said Tuesday it made the determination based on local storm reports showing straight-line winds gusting well over 60 mph (97 kph) from South Dakota and into Iowa, Minnesota and western areas of Illinois and Wisconsin from late Monday into early Tuesday. A storm is classified as a derecho if its wind damage swath extends more than 240 miles (386 kilometers) and has wind gusts of at least 58 mph (93 kph) or greater along most of the length of the storm’s path.

Many areas reported gusts of over 75 mph (121 kph). The highest reading appeared to be in northwestern Iowa just before 10 p.m. Monday, when a gust clocked at 99 mph (159 kph) was recorded at Sioux Center.

The high winds tore down trees and tree limbs throughout the region, damaged some buildings and left thousands of customers without power by midday Tuesday. But the overnight derecho was not nearly as destructive as others in recent history, like one in 2020 that traveled from eastern Nebraska across Iowa and into Wisconsin and Illinois, reaching wind speeds of a major hurricane and flattening an estimated 100,000 trees in and around Cedar Rapids, Iowa.

A December 2021 derecho in the Great Plains and Upper Midwest spawned at least 45 tornadoes, caused widespread damage and killed at least five people.

The overnight storms didn't drop as much rain as was feared, meteorologists said.

“It looks like everything certainly stayed under 2 inches," or 5 centimeters, said Alexis Jimenez, a National Weather Service meteorologist in Des Moines, Iowa.

That could change, at least for Iowa, Tuesday night into Wednesday, Jimenez said.

“It’s southwest Iowa’s turn for thunderstorms with heavy rain,” Jimenez said. “We're looking at maybe some more damaging winds. Of course, none of the magnitude as we saw last night.”

The weather service said severe thunderstorms are expected Tuesday into Wednesday from southern Montana into the central High Plains and across much of Nebraska and Iowa.