This alert expired on 31 August 2026 at 02:00 UTC. It is kept here as a record.
No stronger detection stands among the 13 recorded within 20 km of this point since 15 July 2026 — 9 others scored the same. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Flash Flood Warning issued August 30 at 5:58PM MDT until August 30 at 8:00PM MDT by NWS Grand Junction CO
An estimated 60,358 people live within 50 km of this point.
Nearby, since 15 July 2026
- August 31, 2026 · score 39 · 0.0 km
- July 18, 2026 · score 39 · 2.8 km
- July 22, 2026 · score 39 · 12.7 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 39 out of 100, at 86 % 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) | 39 / 100 |
| Our confidence | 86% |
| Coordinates | 38.7522, -108.8744 |
| Nearest City | Grand Junction (44 km) |
| Population Exposed | 60.4K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-30T23:58:00.000Z |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Mesa, CO |
| Headline | Flash Flood Warning issued August 30 at 5:58PM MDT until August 30 at 8:00PM MDT by NWS Grand Junction CO |
| Expires | 2026-08-30T20:00:00-06:00 |
| SenderName | NWS Grand Junction CO |
| HasExactCoords | true |
| Iem TypeSummary | x |
| Iem City | 6 WNW Castle Valley |
| Iem County | Grand |
| Iem State | UT |
| Iem Wfo | GJT |
| Iem Remark | Debris on UT128 at MM10. Not enough to for the road to become impassable though. |
| MergedSources | [{"id":"iem_x_38.660_-109.500_1788134580000","source":"iem","severity":"low","severityValue":25,"timestamp":1788134580000,"latitude":38.66,"longitude":-109.5}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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 39/100, near Grand Junction (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 191 scientific monitoring sources.