This alert expired on 16 May 2026 at 09:00 UTC. It is kept here as a record.
No stronger detection stands among the 14 recorded within 20 km of this point since 16 March 2026 — 4 others scored the same. The last comparable one was on 13 May 2026. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued May 16 at 3:31AM EDT until May 16 at 5:00AM EDT by NWS Grand Rapids MI
An estimated 62,609 people live within 50 km of this point.
Nearby, since 16 March 2026
- September 4, 2026 · score 32 · 5.1 km
- June 9, 2026 · score 39 · 9.3 km
- May 13, 2026 · score 39 · 10.8 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 82 % 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 | 82% |
| Coordinates | 43.4073, -86.6245 |
| Nearest City | Muskegon (36 km) |
| Population Exposed | 62.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-16T07:31:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.f2b8a87b02cf59b8c7598764824a6ac3bfd653ea.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | South Haven to Holland MI; Holland to Grand Haven MI; Grand Haven to Whitehall MI; Whitehall to Pentwater MI; Pentwater to Manistee MI; Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid Lake; 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; Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake; Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake |
| Headline | Special Marine Warning issued May 16 at 3:31AM EDT until May 16 at 5:00AM EDT by NWS Grand Rapids MI |
| Expires | 2026-05-16T05:00:00-04:00 |
| 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.