Right now
The most recent data we hold from NOAA arrived 21 minutes ago, and this point is in it.
2 other detections within 20 km in the last 24 hours, the nearest <1 km from here.
This alert expired on 17 September 2026 at 06:48 UTC. It is kept here as a record.
It is the 4th strongest of the 43 detections recorded within 20 km of this point since 15 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: Flash Flood Warning issued September 17 at 12:38AM MDT until September 17 at 12:45AM MDT by NWS Grand Junction CO
Urban PEI: 80,247 within a heuristic 50 km radius; not unique people.
Nearby, since 15 March 2026
- July 21, 2026 · score 32 · 15.2 km
- July 23, 2026 · score 39 · 18.9 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 32 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
Computed under scoring rules v5. 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 |
| Legacy data-support index | 0.81/1 |
| Coordinates | 39.2062, -108.3050 |
| Nearest City | Clifton (18 km) |
| Urban exposure index (PEI) | 80.2K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-17T06:38:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.b1cff4e8e8e577dfb59836174fb9e3543e36afdb.001.1 |
Physical priority index · v5. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-09-17T06:38:00.000Z.
First archived: 2026-09-17T06:41:26.465Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Mesa, CO |
| Headline | Flash Flood Warning issued September 17 at 12:38AM MDT until September 17 at 12:45AM MDT by NWS Grand Junction CO |
| Expires | 2026-09-17T00:48:00-06:00 |
| SenderName | NWS Grand Junction CO |
| HasExactCoords | true |
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.
Review the area, threshold and delivery channel in your account.
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