Forecasters warn of up to 4 inches of rain in isolated pockets — with flash flooding possible before the Friday morning commute begins.
A dangerous round of overnight thunderstorms is moving toward southwest Minnesota Thursday evening, bringing the threat of rapid flooding that could make roads impassable and catch sleeping residents off guard before dawn.
Forecasters say storms will develop this evening and push east through the night, with the heaviest rainfall expected to concentrate along the Minnesota River Valley. Most areas in the corridor are forecast to receive over 1 inch of rain — but the real danger comes from isolated locations that could see 4 inches or more if storms repeatedly roll over the same areas.
Communities most at risk include Morris, Granite Falls, Marshall, Tracy, Windom, Fairmont, and Mankato — as well as Hutchinson, Willmar, and nearby towns.
The day will remain mostly dry, but conditions are expected to deteriorate quickly after sunset. Authorities are urging residents to prepare now, before storms arrive.
The primary dangers include flooded city streets, rapidly rising rivers and streams, and flash flooding in areas that drain poorly. Drivers should be especially cautious overnight and into Friday morning — water covering roads can be far deeper than it appears, and even a few inches of moving water can sweep a vehicle off course.
Emergency officials are warning that additional Flood Advisories or Flash Flood Warnings may be issued throughout the night as rainfall rates change. Residents should not wait for a formal warning to act.
Authorities recommend charging all mobile devices before storms arrive, identifying multiple ways to receive emergency alerts overnight — including weather radios — and avoiding any travel on flooded roadways. If water begins entering a home or vehicle, move to higher ground immediately.
The flood threat is expected to continue into Friday morning. Residents across the affected corridor should remain alert and check road conditions before leaving home.