This alert is in force until 1 September 2026, 23:45 UTC.
It is the 5th strongest of the 39 detections recorded within 20 km of this point since 15 March 2026. The last comparable one was on 31 August 2026.
What the source measured
NOAA reported: Flash Flood Warning issued September 1 at 3:46PM MDT until September 1 at 5:45PM MDT by NWS Grand Junction CO
An estimated 80,247 people live within 50 km of this point.
Nearby, since 15 March 2026
- September 1, 2026 · score 32 · 10.8 km
- July 21, 2026 · score 39 · 14.8 km
- July 23, 2026 · score 39 · 17.7 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 32 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) | 32 / 100 |
| Our confidence | 86% |
| Coordinates | 39.0750, -108.6740 |
| Nearest City | Grand Junction (11 km) |
| Population Exposed | 80.2K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-01T21:46:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.ce0578d9ff659db482302f04015b5e235a7efeb2.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Mesa, CO |
| Headline | Flash Flood Warning issued September 1 at 3:46PM MDT until September 1 at 5:45PM MDT by NWS Grand Junction CO |
| Expires | 2026-09-01T17:45:00-06:00 |
| SenderName | NWS Grand Junction CO |
| HasExactCoords | true |
| Iem TypeSummary | R |
| Iem Magnitude | 0.67 |
| Iem Unit | Inch |
| Iem City | 3 SSE Redlands |
| Iem County | Mesa |
| Iem State | CO |
| Iem Wfo | GJT |
| MergedSources | [{"id":"iem_R_39.040_-108.630_1788301140000","source":"iem","severity":"low","severityValue":25,"timestamp":1788301140000,"latitude":39.04,"longitude":-108.63}] |
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.
Want to know when something happens near Grand Junction?
Calamity.live data shows a weather event with CalamityScore 32/100, near Grand Junction (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.