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Flash Flood — Sioux, IA

Jun 2, 2025

Scattered strong to severe thunderstorms developed late afternoon along a slow-moving frontal boundary. Even with fairly weak deep-layer shear, strong instability resulted in large hail. Drier air and advancing cold pools later in development produced spotty damaging winds. High moisture content and slowly progressing storms also produced some locally heavy rainfall with rates briefly from 3 to 5 inches per hour.

Source: NOAA National Weather Service Storm Events Database (event 1278631). Narrative written by NWS staff at the time of the event.

Flood Risk Context for Sioux, IA

This event is one of many recorded floods in Sioux County. See the full FEMA flood zone map, NFIP claim totals, and disaster history for the area.

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