SIOUX FALLS, S.D. (KELO) — It was a deadly storm and an expensive storm. 

One year ago, temperatures climbed to the mid 90s creating the energy for a line of severe thunderstorms that combined for a derecho. That storm event produced more than 150 damaging wind reports, 59 significant wind gusts (75 mph or higher) and resulted in two deaths in South Dakota. The National Centers for Environmental Information listed the May 12, 2022 derecho as a billion-dollar disaster event. 

The NCEI counted the May 12, 2022 derecho as one of 18 separate weather and climate disasters costing at least $1 billion. The worst weather disaster in 2022 was Hurricane Ian, which caused $112.9 billion and 152 deaths. 

  • Powerlines down along 33rd Street near Augustana University | Courtesy Nick Anderson
  • Brookings tree damage after May 12 storm
  • Tree damage in Brookings following May 12 storm
  • Power pole down at 26th Street and Williams Avenue
  • Damage to Great Shots in Sioux Falls

The May 12, 2022 derecho, which started as thunderstorms in southern Nebraska, produced 34 tornadoes in four different states: 19 in Minnesota, 13 in South Dakota and 1 in both North Dakota and Iowa. Xcel Energy reported power was out for more than 35,000 customers, while Northwestern Energy had as many as 9,500 customers without power.

The Sioux Falls National Weather Service said many vehicles were blown off roads and the storm shut down traffic on Interstate 29 and 90 as the storm contained “incredible amounts of dust and debris northward, leading to near zero visibility as the storms passed across the area.” 

What is a derecho? 

KELOLAND meteorologist Scot Mundt described derechos as “widespread, long-lived wind storms with a broad band of showers or thunderstorms.” The National Weather Service defines derechos by wind damage extending more than 240 miles long. 

This graphic shows the climatology of derechos in the United States. While it shows central and western South Dakota average one every four years, it shows one every two years in eastern KELOLAND.

Notice the area with the most derechos is where Oklahoma, Missouri and Arkansas meet.

For some thunderstorms, heavy rain can be the main threat. In others, hail or strong winds are the biggest threat. In more rare instances, thunderstorms can develop into derechos.