This alert expired on 10 August 2026 at 07:30 UTC. It is kept here as a record.
It is the 8th strongest of the 20 detections recorded within 20 km of this point since 13 May 2026. The last comparable one was on 28 July 2026. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued August 10 at 1:31AM EDT until August 10 at 3:30AM EDT by NWS Grand Rapids MI
Nearby, since 13 May 2026
- June 11, 2026 · score 16 · 5.2 km
- July 4, 2026 · score 22 · 15.6 km
- June 16, 2026 · score 34 · 15.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 22 out of 100, at 61 % 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) | 22 / 100 |
| Our confidence | 61% |
| Coordinates | 42.4467, -86.5244 |
| Nearest City | Holland (51 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-10T05:31:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.1dbba129ed78bfd2c319c246a469a77970314bcd.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | St Joseph to South Haven MI; South Haven to Holland MI; Holland to Grand Haven MI; 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; Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued August 10 at 1:31AM EDT until August 10 at 3:30AM EDT by NWS Grand Rapids MI |
| Expires | 2026-08-10T03:30:00-04:00 |
| 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 22/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.