Verified storm · closed
1.2–4" hail crossed Fall River County, SD — August 21, 2026
Measured against the NOAA MRMS national radar feed on its 2-minute cycle — a verified event, not a forecast.
Storm stats
| County | Fall River County, SD |
|---|---|
| Max hail (MESH) | 4" |
| Mean hail (MESH) | 1.2" |
| Swath area | 438 mi² (1,134 km²) |
| Radar cells (~1 km grid) | 1,252 |
| First radar detection | 2026-08-21 21:10 UTC |
| Last radar detection | 2026-08-22 01:02 UTC |
| Verified | 2026-08-21 21:13 UTC |
| Swath centroid | 43.0263, -103.0411 |
| Storm ID | sw_da209140 |
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Fall River County, SD — verified storm record
Swath has 41 radar-verified hail storms on record for Fall River County, SD going back to August 2025, the largest measuring 5.37″. Every one was measured against NOAA MRMS radar — not estimated, and not a forecast.