This alert is in force until 2 September 2026, 21:30 UTC.
It is the 3rd strongest of the 24 detections recorded within 20 km of this point since 1 April 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Flash Flood Warning issued September 2 at 12:37PM MDT until September 2 at 3:30PM MDT by NWS Grand Junction CO
An estimated 80,247 people live within 50 km of this point.
Nearby, since 1 April 2026
- September 1, 2026 · score 32 · 9.3 km
- July 21, 2026 · score 39 · 15.1 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.
Computed under scoring rules v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 32 / 100 |
| Our confidence | 86% |
| Coordinates | 39.0775, -108.7813 |
| Nearest City | Grand Junction (20 km) |
| Population Exposed | 80.2K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-02T18:37:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.663443da938e7db9d4a6c151a8a6a3856556e2e8.001.1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Mesa, CO |
| Headline | Flash Flood Warning issued September 2 at 12:37PM MDT until September 2 at 3:30PM MDT by NWS Grand Junction CO |
| Expires | 2026-09-02T15:30:00-06:00 |
| SenderName | NWS Grand Junction CO |
| HasExactCoords | true |
| Iem TypeSummary | R |
| Iem Magnitude | 0.7 |
| Iem Unit | Inch |
| Iem City | 40 NE Elgin |
| Iem County | Grand |
| Iem State | UT |
| Iem Wfo | GJT |
| Iem Remark | Mesonet station EWCU1 37.6 NE Green River (SNOTEL). |
| MergedSources | [{"id":"iem_R_39.100_-108.700_1788376140000","source":"iem","severity":"low","severityValue":25,"timestamp":1788376140000,"latitude":39.1,"longitude":-108.7},{"id":"iem_R_39.100_-108.730_1788357600000","source":"iem","severity":"low","severityValue":25,"timestamp":1788357600000,"latitude":39.1,"longitude":-108.73},{"id":"iem_R_39.040_-108.630_1788354000000","source":"iem","severity":"low","severityValue":25,"timestamp":1788354000000,"latitude":39.04,"longitude":-108.63},{"id":"iem_N_39.600_-108.820_1788370320000","source":"iem","severity":"low","severityValue":25,"timestamp":1788370320000,"latitude":39.6,"longitude":-108.82},{"id":"iem_R_39.140_-108.710_1788354000000","source":"iem","severity":"low","severityValue":25,"timestamp":1788354000000,"latitude":39.14,"longitude":-108.71},{"id":"iem_R_39.310_-109.530_1788372000000","source":"iem","severity":"low","severityValue":25,"timestamp":1788372000000,"latitude":39.31,"longitude":-109.53}] |
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 8 March 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.