Hail in Grant County, South Dakota

Hail August 21, 2025 · Grant County, South Dakota

1 in

Hail diameter

Where the report was made, with tornadoes recorded within 15 miles over the years.

The wider storm

Storms moving south across northeast South Dakota produced hail and heavy rain, leading to flash flooding around the Watertown area.

The resultant runoff would also later result in flooding of the Big Sioux and surrounding tributaries around the Watertown and Castlewood areas.

Began near Big Stone City (45.3100, -96.5100).

Source: NOAA Storm Events Database, event 1291018. Narratives are written by the National Weather Service forecast office that issued the report.

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