Flash Flood — Decatur, Iowa

2025-06-29 · near Leon, Decatur, Iowa

Event narrative

Heavy rain occurred over the area with over 3 inches in an hour. This resulted in a number of flooded roads in town, with water actively flowing at mid rim height on vehicles in flood waters. Impacts were largely confined to town which lies lower that surroundings area. Highway 69, coming into town from the north, had water over it for a time but this remained minor enough that a road closure was not needed.

Wider weather episode

On the morning of June 29th robust thunderstorms set up across Decatur county, part of a larger system that dropped across South Dakota and Nebraska into Iowa and merging with convection out of Missouri with increasing moisture convergence. All the ingredients for heavy, efficient rain was in place. PWATs exceeded two inches with deep warm cloud layers and very slow mean flow under 15 kts. This resulted in pockets of heavy rain, including over Decatur Iowa where three inches of rain fell in an hour. This heavy rain resulted in a number of road closures in town and water flowing through streets at about mid rim on cars in the flood waters.

View location on OpenStreetMap → (40.7556, -93.7375)

Source: NOAA Storm Events Database, event_id 1276259. Narrative written by the NWS forecast office that issued the report.