Right now
The most recent data we hold from NOAA arrived 4 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 18 September 2026 at 21:00 UTC. It is kept here as a record.
It is the 19th strongest of the 38 detections recorded within 20 km of this point since 13 May 2026. Another comparable one was recorded here earlier the same day. 17 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued September 18 at 2:24PM MDT until September 18 at 3:00PM MDT by NWS Salt Lake City UT
Urban PEI: 477,263 within a heuristic 50 km radius; not unique people.
Nearby, since 13 May 2026
- September 18, 2026 · score 46 · 7.3 km
- June 25, 2026 · score 52 · 10.1 km
- September 18, 2026 · score 54 · 12.0 km
How we know
2 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 37 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) | 37 / 100 |
| Legacy data-support index | 0.86/1 |
| Coordinates | 40.6448, -111.3041 |
| Nearest City | Cottonwood Heights (43 km) |
| Urban exposure index (PEI) | 477.3K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-18T20:24:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.2c472e08841d2b062f816e4e725e5ef40cde3dc5.001.1 |
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: 2026-09-18T20:24:00.000Z.
First archived: 2026-09-18T20:31:01.881Z. 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 | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Davis, UT; Morgan, UT; Salt Lake, UT; Weber, UT; Morgan, UT; Weber, UT; Carbon, UT |
| Headline | Severe Thunderstorm Warning issued September 18 at 2:24PM MDT until September 18 at 3:00PM MDT by NWS Salt Lake City UT |
| Expires | 2026-09-18T15:00:00-06:00 |
| SenderName | NWS Salt Lake City UT |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.2c472e08841d2b062f816e4e725e5ef40cde3dc5.001.1","noaa_urn:oid:2.49.0.1.840.0.3dc5b24fbd083a5eae614025ac9e249b21a6724f.001.1","noaa_urn:oid:2.49.0.1.840.0.35f613ef4ea6dd18eb6a628a34b010b1dc1dd95e.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 0.5 |
| Iem Unit | Inch |
| Iem City | 1 W Holladay |
| Iem County | Salt Lake |
| Iem State | UT |
| Iem Wfo | SLC |
| Iem Remark | Report from mPING: Half-inch (0.50 in.). |
| MergedSources | [{"id":"iem_H_40.170_-111.750_1789742460000","source":"iem","severity":"low","severityValue":25,"timestamp":1789742460000,"latitude":40.17,"longitude":-111.75},{"id":"iem_H_40.670_-111.840_1789742160000","source":"iem","severity":"low","severityValue":25,"timestamp":1789742160000,"latitude":40.67,"longitude":-111.84}] |
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 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.
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