Eastern South Dakota, eastern Nebraska and western Minnesota felt the brunt of Mother Nature late-afternoon, early evening of May 12 when what the U.S. National Weather Service has classified as a derecho made its way through the area.
Winds gusted as high as 97 miles per hour near Madison, S.D., with an unofficial report of 107 mph near Tripp, S.D. A tornado caused damage in and around Castlewood, S.D., and on May 13 South Dakota Gov. Kristi Noem issued a state of emergency and ordered state personnel and resources to communities impacted. The Department of Public Safety’s Office of Emergency Management has opened an Emergency Operations Center to coordinate the response with local government authorities.
Noem toured some of the storm-ravaged areas to survey the damage.
Media reports indicate two fatalities linked to the storms.
According to the Sioux Falls NWS office, a strong line of thunderstorms developed across southern Nebraska and quickly raced northeast. As these storms moved north, they produced extreme winds across portions of the Northern Plains. Widespread straight-line winds between 50 and 70 mph were reported, with smaller areas of 80 to 100 mph winds. The highest wind gusts reported included a measured 107 mph gust in Tripp, S.D., 97 mph wind gust in Madison, S.D. and a 90 mph wind gust in Huron, S.D.
A second line of thunderstorms the evening of May 12 developed in eastern Nebraska and lifted northeast across portions of Iowa, Minnesota and extreme eastern South Dakota. While weaker, these storms continued to produce wind gusts between 50 and 87 mph.
According to the NWS, the collection of storms will be considered a “derecho,” which by definition is a long-lasting storm system capable of producing extreme winds and damage over an extended area of space and time. Significant damage to residential, commercial and agricultural areas was reported in many communities across the Tri-State area. Vehicles and high-profile vehicles were blown off several roads, shutting down traffic on interstate highways 29 and 90.
In addition to structural damage, the high winds caused downed powerlines and some areas were still reporting power outages the afternoon of May 13.