This alert expired on 22 June 2026 at 04:04 UTC. It is kept here as a record.
It is the 3rd strongest of the 206 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 21 at 9:54PM MDT until June 21 at 10:00PM MDT by NWS Denver CO
An estimated 1,855,722 people live within 50 km of this point.
Nearby, since 12 March 2026
- May 5, 2026 · score 52 · 9.1 km
- March 13, 2026 · score 58 · 9.1 km
- March 12, 2026 · score 58 · 9.1 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 52 out of 100, at 78 % 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) | 52 / 100 |
| Our confidence | 78% |
| Coordinates | 40.0200, -105.3500 |
| Nearest City | Boulder (7 km) |
| Population Exposed | 1.9M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-22T03:54:00.000Z |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Boulder, CO |
| Headline | Severe Thunderstorm Warning issued June 21 at 9:54PM MDT until June 21 at 10:00PM MDT by NWS Denver CO |
| Expires | 2026-06-21T22:04:00-06:00 |
| SenderName | NWS Denver CO |
| HasExactCoords | true |
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 52/100, near Boulder (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.