EF1 tornado in Cottonwood County, Minnesota

A tornado spun up around one mile west-southwest of Storden just southeast of the intersection of State Highway 30 and 370th Avenue. The tornado tracked northeast and crossed a slough where grasses exhibited a convergent pattern. The tornado then moved into the northwest edge of Storden where it destroyed a 500,000 bushel commercial grain bin and tossed the debris onto an adjacent office structure. The tornado lifted before reaching County Road 5. The estimated maximum wind speed was 95 mph and the average path width was 50 yards.

A cluster of early morning storms developed on the nose of steeper mid-level lapse rates and marginally strong elevated wind shear across far southeast South Dakota. Multicell convection produced spotty large hail moving into southwest Minnesota. During the afternoon, convection re-ignited near an advancing mesoscale convective vortex and moved northeast from eastern Nebraska into southwest Minnesota. With greater surface-based instability with a MLCAPE of 2000-3000 J/kg and deep-layer shear of 40-50 knots, storms quickly organized into a QLCS structure and produced hail up to ping-pong ball size, wind to 90 mph, and a few tornadoes across southwest Minnesota. Presidential Disaster Declarations were granted to Cottonwood and Nobles Counties for damages to public infrastructure.