SIOUX FALLS, S.D. — A violent and fast-moving thunderstorm complex tore through northwest Iowa and the Sioux Falls corridor early Sunday morning, June 28, 2026, unleashing wind gusts of 60 mph or greater capable of snapping power lines, toppling trees, and causing structural damage — and it is not done yet.
The storm was moving east and southeast as of 5:55 AM, pushing directly toward a densely populated corridor of towns with little time to prepare.
What the Radar Is Showing
Radar showed a large, well-organized thunderstorm cluster stretching from the Sioux Falls area southward through Spencer and toward Fort Dodge. The most intense activity — marked by deep red returns on radar — was concentrated near the core of the system around Sioux Falls and Spencer, indicating the heaviest rainfall and most dangerous wind threat remained locked in those zones.
Severe thunderstorm warnings were in effect for multiple counties as the complex tracked east-southeast toward Mason City and Austin.
Who Is in the Path Right Now
Communities directly in the storm’s path include Spencer, Fort Dodge, Mason City, and Austin. Residents further east — including Waterloo and surrounding communities in north central Iowa — should expect deteriorating conditions as the system continues pushing through the region throughout the morning hours.
The organized and fast-moving nature of this complex means damaging winds can arrive with almost no warning ahead of the main line.
What You Need to Do Immediately
Residents across the warned zone are urged to get into a sturdy interior room on the lowest floor of a building, away from windows, and to avoid all unnecessary travel until the storm has fully passed their area.
Do not wait to see or hear the storm before taking shelter. By the time it is visible, it may already be too late to act safely.
Stay indoors. The storm is moving fast.
