This alert expired on 4 July 2026 at 22:45 UTC. It is kept here as a record.
No stronger detection stands among the 49 recorded within 20 km of this point since 14 April 2026 — 23 others scored the same. Another comparable one was recorded here earlier the same day. 12 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 4 at 5:54PM EDT until July 4 at 6:45PM EDT by NWS Detroit/Pontiac MI
An estimated 2,309,930 people live within 50 km of this point.
Nearby, since 14 April 2026
- June 25, 2026 · score 52 · 1.8 km
- July 18, 2026 · score 52 · 3.5 km
- May 19, 2026 · score 52 · 6.4 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 52 out of 100, at 78 % 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) | 52 / 100 |
| Our confidence | 78% |
| Coordinates | 42.5935, -82.7050 |
| Nearest City | Mount Clemens (14 km) |
| Population Exposed | 2.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-04T21:54:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.732006dc4b432ed6df05dbe401e27df9292c50ff.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | St. Clair River; Detroit River; Lake St. Clair Open Lake (U.S. Portion) |
| Headline | Special Marine Warning issued July 4 at 5:54PM EDT until July 4 at 6:45PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-07-04T18:45:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
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 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 52/100, near Mount Clemens (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.