Torrential Rainfall Triggers Flash Flooding and Highway Mudslides Across Southern Minnesota

Early Saturday morning, September 19, 2026, floodwaters breached the banks of the Root River and its tributaries, submerging municipal road networks across southern Minnesota after a stalled frontal system deposited more than eight inches of rain. The deluge, which began late Friday, rapidly overwhelmed local drainage infrastructure, prompting emergency declarations and widespread road closures across Fillmore, Mower, and Houston counties.[2][4]

The heaviest precipitation concentrated in the southeastern quadrant of the state. Readings submitted to the Community Collaborative Rain, Hail and Snow Network recorded 8.29 inches in Houston, while Spring Valley registered over eight inches and Lanesboro received 7.71 inches.[1][4]

Further north, the system broke long-standing daily records. The Rochester airport recorded 2.35 inches by midnight Friday, shattering the previous September 18 daily rainfall record established in 2003.

The rapid accumulation of water destabilized saturated terrain, triggering multiple mudslides that severed state transportation arteries. On State Highway 16 east of Lanesboro, a rain-soaked hillside collapsed, depositing mud, trees, and debris across the roadway and forcing the Minnesota Department of Transportation to close the route for several hours Saturday morning. Additional mudslides were reported overnight along State Highway 76 near Caledonia, while floodwaters encroached on State Highways 16 and 44 in Hokah, prompting police to restrict access to the area surrounding Como Falls.[2][3]

Municipal authorities scrambled to secure downtown corridors as creeks and rivers overtopped their banks. In Spring Valley, Mayor Justin Mlinar announced just after 6:00 a.m. Saturday that all city streets were closed due to flooding, urging residents to avoid driving through inundated areas. By 10:00 a.m., only a single street had been reopened to traffic.[1][2]

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Similar containment efforts unfolded in New Richland, where municipal officials opened sandbag distribution sites for displaced residents. "Please respect road closures, barricades, and warnings and our staff and volunteers," the city government urged in a public statement just after 7:00 a.m. The Waseca County Sheriff's Office published a rolling list of local road closures, while the Austin Police Department reiterated warnings as rising waters on the Cedar River forced the closure of several streets late Saturday afternoon.[1][2]

The hydrological load continues to move downstream, threatening commercial and recreational properties situated in low-lying floodplains. The Old Barn Resort, located along the Root River between Lanesboro and Preston, reported severe flooding across its riverside golf course, forcing an indefinite closure and the cancellation of a weekend tournament.[1][2]

Emergency management officials are now monitoring river gauges as the runoff consolidates into larger waterways. In Houston County, the Root River is projected to reach a crest of 15.6 feet by Sunday afternoon. If realized, that level would surpass the minor lowland flooding threshold of 15 feet and mark the highest crest the river has experienced in more than 15 years, testing the resilience of the region's flood mitigation infrastructure.[4]