We are finishing up what was a very stormy weekend across KELOLAND. Friday night brought the greatest threat to areas east of I-29. We had a few tornadoes reported in western Minnesota during the afternoon including this tornado which dropped near Revere, MN. This storm was spotted and photographed by chasers Marc Hicks and Mike Vetter of the Extreme Weather Chase Team.
Thankfully, the tornado didn’t stay on the ground very long and didn’t cause any structural damage. The storms then formed a line and began working south. The main threat then transitioned to straightline winds, heavy rain and hail. That is until the storms made it into northwest Iowa, at that point the line of storms developed a stronger supercell on the very end of the line of storms. This is a set up which is called a “Tail-End Charlie.” The supercell on the end of the line and is tapping into the warm humid air and cycling over and over again. This part of the storm then produced an EF-1 (86-110 mph) tornado near Little Rock, IA and then an EF-4 (166-200 mph) tornado which hit Sibley, IA. The storm did some major damage and then proceeded to drop several more tornados through Osceola, O’Brien and Cherokee counties. It was an intense event for all of northwest Iowa and the clean up is expected to take a very long time.
Saturday also brought a significant chance for very strong thunderstorms across eastern South Dakota. We had tons of heat and humidity and a number of elements to spark the storms. We also had wind shear (winds moving in different directions at different heights in the atmosphere) this is the main component for tornadic activity. The storms didn’t disappoint with several tornado warnings and 3 confirmed tornadoes. There was a report of a tornado up near Carthage, SD and two more in northwest Iowa. The main damaging threat from the storms came with damaging straightline winds which affected a huge part of eastern South Dakota. We also had a tremendous amount of rain which caused significant flash flooding. Many areas will continue to deal with flooding as the rain water works into local streams and rivers. Below is a picture from south of Sioux Falls in Harrisburg where there was significant wind damage, it was sent in by Ann Fleming.
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