Hail — Black Hawk, Iowa

2025-09-15 · near La Porte City Arpt, Black Hawk, Iowa

Event narrative

Spotter submitted picture of hail larger than a quarter north of Irvine Prairie. Delayed report, time and location estimated with radar.

Wider weather episode

Iowa remained under the influence of a robust thermal ridge across the area, resulting in an unstable environment of 2000-3000 J/kg of MLCAPE but weak shear under 20 kts. There was no focused forcing mechanism in place, however by late afternoon temperatures had warm enough for diurnal thunderstorm development. Despite the lack of shear, one storm did result in half dollar sized hail in Black Hawk County.

View location on OpenStreetMap → (42.3400, -92.3000)

Source: NOAA Storm Events Database, event_id 1297989. Narrative written by the NWS forecast office that issued the report.