This alert expired on 13 May 2026 at 02:31 UTC. It is kept here as a record.
No stronger detection stands among the 20 recorded within 20 km of this point since 16 March 2026 — 3 others scored the same. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 12 at 10:21PM EDT until May 12 at 10:30PM EDT by NWS Grand Rapids MI
An estimated 62,609 people live within 50 km of this point.
Nearby, since 16 March 2026
- May 16, 2026 · score 39 · 10.8 km
- September 4, 2026 · score 32 · 13.5 km
- July 9, 2026 · score 22 · 14.3 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 39 out of 100, at 81 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Computed under scoring rules v1. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 39 / 100 |
| Our confidence | 81% |
| Coordinates | 43.5017, -86.6550 |
| Nearest City | Muskegon (45 km) |
| Population Exposed | 62.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-13T02:21:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.4b24ffb7f60fcfb9620e9ad3f89e9cb32673974d.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Grand Haven to Whitehall MI; Whitehall to Pentwater MI; Lake Michigan from Whitehall to Pentwater MI 5NM offshore to Mid Lake; Lake Michigan from Grand Haven to Whitehall MI 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued May 12 at 10:21PM EDT until May 12 at 10:30PM EDT by NWS Grand Rapids MI |
| Expires | 2026-05-12T22:31:00-04:00 |
| SenderName | NWS Grand Rapids 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 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 in this area?
Calamity.live data shows a weather event with CalamityScore 39/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.