WENTWORTH, S.D. — Mark Mergen was driving on a gravel road from his farm bin site north of Wentworth, South Dakota, to his home near Dell Rapids, South Dakota, when his vehicle was overtaken by a freak storm.

“I tried to outrun it,” Mergen said of the Thursday, May 12, storm. “I was going 65 and it just engulfed me. It was like the movie, ‘Twister.’ There was so much dirt flying around. I think if a guy was outside, it would’ve killed them because you wouldn’t be able to breathe. Within a quarter-mile the dirt was ungodly – thick – and it just blew like a son-of-a-buck.”

Mergen said 100,000 bushels of his 150,000 bushel bin site was damaged, some heavily damaged or destroyed.

Mergen, 70, says it’s a kind of storm he’s never seen before. The National Weather Service had clocked winds at Wentworth at 96 mph. Winds ranged from 90 mph to 100 mph in many places, topping out at 107 mph at Mesonet, near the town of Tripp.

Laura Edwards, South Dakota State University Extension Service state climatologist based at Aberdeen, said the National Weather Service in Aberdeen and Sioux Falls, South Dakota, had confirmed the storm as a “derecho.”

According to the National Weather Service, a derecho (pronounced similar to "deh-REY-cho") is a widespread, long-lived wind storm that is associated with a band of rapidly moving showers or thunderstorms.

Everyone’s safe. Some structural damage and a silo ripped pic.twitter.com/ud2jXyOI8Q

Although a derecho can produce destruction similar to the strength of tornadoes, the damage typically is directed in one direction along a relatively straight swath. As a result, the term "straight-line wind damage" sometimes is used to describe derecho damage. By definition, if the wind damage swath extends more than 240 miles (about 400 kilometers) and includes wind gusts of at least 58 mph or greater along most of its length, then the event may be classified as a derecho.

The storm moved through at 60 mph to 70 mph. Damage in South Dakota was generally east of U.S.Highway 281, which runs from west of Mitchell to Aberdeen. Western Area Power Administration had a high number of broken poles from Flandreau to Watertown. Rainfall totals generally were less than a half-inch, but up to an inch in some locations. “Not a lot of moisture,” Edwards said.

Power was interrupted for thousands, including the city of Brookings, South Dakota, for much of the day on May 13. Brookings Municipal Utilities informed their Swiftel customers that landline phones were unavailable to nearly all areas of Brookings until the power was restored, and that the electric power supplier had “not informed” BMU Of an estimated time for power restoration.

Edwards said the storm is unique in recent history for South Dakota, except for 2020, when a similar storm came through in June. The same storm went through Iowa, ripping a path through crops across the northern tier of the state. Some parts of Minnesota were also hit.

Looks real similar here pic.twitter.com/EjggI5wLdO

Edwards said the May 12, 2022, storm had only two or three tornadoes. The National Weather Service is in the process of confirming and classifying the tornadoes, Edwards said. One apparent tornado tore through the farming community of Castlewood, South Dakota, which is the hometown of South Dakota Gov. Kristi Noem. The storm also heavily damaged a school in Flandreau and killed one person in the Sioux Falls, according to the Sioux Falls Argus Leader.

One person also was killed in a grain bin collapse at Blomkest in west-central Minnesota south of Willmar. A second tornado was suspected near New Effington, South Dakota, in Roberts County.

Edwards said the storm will be remembered for producing the second-highest number of “significant wind” events on record. There were 55 reporting sites that clocked winds at hurricane-force, at 75 mph or greater. The highest previous number was in 2004.

“It damaged quite a few farm structures – pole barns, metal structures on farms, a lot of grain bins – anything metal that didn’t have anything inside, holding it together,” she said.

Edwards said that South Dakota planting had gotten off to a slow start and that damage to the equipment and structures will likely “set things back.”

She said that one outstanding storm doesn’t make a trend. “It was just a convergence of all of the ingredients at just the right time,” she said. “Everyone I’ve visited with have never seen a storm like this.”

Mergen farms with his son Kyle, 35, and their employee Mitch Packard. They have about 90% of their corn planted, but 20% is “flooded out.” They haven’t started soybean planting yet.

Mark said it’s been a weird year: “Dry, dry, cold, cold, now we’re wet, humid and wind.”

Kyle, who had been in a basement during the storm, said, it makes him nervous about what might come next.

“I think some goofy business is going on,” Kyle said, referring to strange weather and world turmoil. He didn’t, however, see it as a sign of climate change, explaining, “We’ve had storms like this before,” he said.

Minnesota Gov. Tim Walz on May 13, 2022, for 30 days ordered temporary regulatory relief for motor carriers and drivers supporting spring cropping, citing flooding and delayed planting.