Severe thunderstorms swept across Siouxland on May 17, 2026, bringing large hail, damaging winds and tornado potential as warnings went up in South Dakota and Nebraska. A severe thunderstorm warning was in effect for Bon Homme County, Yankton County and southeastern Hutchinson County in southeastern South Dakota, while another warning covered Knox County, Nebraska.
At 2:49 PM CDT, a storm was located near Avon, or 13 miles west of Tyndall, and was moving east at 50 mph. Radar indicated the storm was producing 70 mph wind gusts and ping pong ball size hail. The warning said people and animals outdoors could be injured, and that hail damage to roofs, siding, windows and vehicles was expected, along with considerable tree damage and wind damage to mobile homes, roofs and outbuildings.
The storm near Avon was expected to be near Tyndall, Springfield and Avon around 2:55 PM CDT, with Tabor, Scotland and Utica also in its path. In Nebraska, the severe thunderstorm warning for Knox County remained in effect until 3:15 PM as that storm produced 1 inch hail and 60 mph wind gusts while moving northeast at 45 mph.
The weather threat came as tornado watches were issued across most of Siouxland, keeping much of the region under alert until 10 PM on May 17, 2026. That left a broad corridor of communities watching the sky for the kind of fast-moving, radar-indicated storms that can turn a routine afternoon into a scramble for cover.
For now, the risk is clear: the storms were already producing destructive hail and wind, and the warnings covered communities in the direct path. Anyone in the affected counties had a short window to get inside before the next round of damaging weather arrived.
