Reported by SPC today.
No stronger detection stands among the 52 recorded within 20 km of this point since 22 March 2026 — 10 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
SPC reported: Wind 59 kt near 17 W Castle Rock, Butte, SD. (UNR)
How we know
Confirmed by 5 independent sources, including SPC.
Our own score for this event is 22 out of 100, at 66 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 22 / 100 |
| Our confidence | 66% |
| Coordinates | 44.9700, -103.7700 |
| Nearest City | Rapid City (108 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-30T21:55:00.000Z |
| Source | https://www.spc.noaa.gov/climo/reports/today.html |
Score Breakdown
Technical Details
| ReportType | wind |
| Speed | 59 |
| Location | 17 W Castle Rock |
| County | Butte |
| State | SD |
| Comments | (UNR) |
| Iem TypeSummary | G |
| Iem Magnitude | 55 |
| Iem Unit | mph |
| Iem City | 17 W Castle Rock |
| Iem County | Butte |
| Iem State | SD |
| Iem Wfo | UNR |
| MergedSources | [{"id":"iem_G_44.970_-103.770_1788125700000","source":"iem","severity":"low","severityValue":25,"timestamp":1788125700000,"latitude":44.97,"longitude":-103.77},{"id":"iem_G_44.970_-103.770_1788126900000","source":"iem","severity":"low","severityValue":25,"timestamp":1788126900000,"latitude":44.97,"longitude":-103.77},{"id":"iem_G_45.070_-103.780_1788128100000","source":"iem","severity":"low","severityValue":25,"timestamp":1788128100000,"latitude":45.07,"longitude":-103.78},{"id":"iem_G_44.970_-103.770_1788126300000","source":"iem","severity":"low","severityValue":25,"timestamp":1788126300000,"latitude":44.97,"longitude":-103.77}] |
Safety Information
Always follow official guidance from your local emergency management agency. This platform provides scientific monitoring data and is not a substitute for official warnings. If you are in immediate danger, contact your local emergency number.
Series begins 10 February 2026. Comparisons refer to that period only. Collection gap: 14-26 August 2026.
This data is aggregated algorithmically from scientific sources. Not a replacement for official emergency warnings.
Calamity.live data shows a weather event with CalamityScore 22/100, near Rapid City (United States), based on data from spc. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.