Keloland Weather reported tornado watches across most of Siouxland on May 17, 2026, with the alerts set to stay in effect until 10 PM tonight. The same afternoon, severe thunderstorms were developing in the region and producing large hail, damaging winds and tornado potential.
At 2:49 PM CDT, the National Weather Service in Sioux Falls issued severe thunderstorm warnings for Bon Homme County, Yankton County and southeastern Hutchinson County in southeastern South Dakota. A separate warning was issued in Knox County, Nebraska, until 3:15 PM.
Avon Storm Near Tyndall
The storm near Avon was located about 13 miles west of Tyndall and was moving east at 50 mph. It was producing 70 mph wind gusts and ping pong ball size hail, and it was radar indicated. The storm was expected near Tyndall, Springfield and Avon around 2:55 PM CDT, with Tabor, Scotland and Utica also in its path.
Knox County Warning
In Knox County, the severe thunderstorm warning covered a storm producing 1 inch hail and 60 mph wind gusts as it moved northeast at 45 mph. The warning there remained in effect until 3:15 PM, keeping part of southeastern Nebraska under a separate alert while watches spread across most of Siouxland.
The sequence left most of Siouxland under a tornado watch while multiple counties dealt with separate severe thunderstorm warnings. For people in the warned areas, the immediate step was to stay alert to changing conditions through the evening, since the tornado watches remained in place until 10 PM tonight.
