This alert expired on 9 May 2026 at 20:00 UTC. It is kept here as a record.
No stronger detection stands among the 52 recorded within 20 km of this point since 14 April 2026 — 28 others scored the same. Another comparable one was recorded here earlier the same day. 6 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 9 at 3:29PM EDT until May 9 at 4:00PM EDT by NWS Detroit/Pontiac MI
An estimated 2,765,826 people live within 50 km of this point.
Nearby, since 14 April 2026
- July 4, 2026 · score 52 · 3.2 km
- May 19, 2026 · score 52 · 6.0 km
- May 19, 2026 · score 52 · 7.8 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 52 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) | 52 / 100 |
| Our confidence | 86% |
| Coordinates | 42.5081, -82.7900 |
| Nearest City | Saint Clair Shores (8 km) |
| Population Exposed | 2.8M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-09T19:29:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.6f2b4c4edcc37132daa4f9561e15218b44795205.001.1 |
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 May 9 at 3:29PM EDT until May 9 at 4:00PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-09T16:00:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| Iem TypeSummary | H |
| Iem Magnitude | 1 |
| Iem Unit | inch |
| Iem City | 2 E Clarkston |
| Iem County | Oakland |
| Iem State | MI |
| Iem Wfo | DTX |
| MergedSources | [{"id":"iem_H_42.730_-83.380_1778351220000","source":"iem","severity":"low","severityValue":25,"timestamp":1778351220000,"latitude":42.73,"longitude":-83.38}] |
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 Saint Clair Shores (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.