This alert expired on 2 September 2026 at 12:30 UTC. It is kept here as a record.
It is the 11th strongest of the 21 detections recorded within 20 km of this point since 16 March 2026. The last comparable one was on 8 July 2026.
What the source measured
NOAA reported: Special Marine Warning issued September 2 at 6:55AM EDT until September 2 at 8:30AM EDT by NWS Grand Rapids MI
Nearby, since 16 March 2026
- July 1, 2026 · score 22 · 11.2 km
- June 10, 2026 · score 16 · 17.8 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 16 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 v4. Rows carrying other versions were judged by different rules and are not directly comparable.
Event Data
| Type | Severe Weather |
| Severity | Medium |
| Calamity Score (ours) | 16 / 100 |
| Our confidence | 61% |
| Coordinates | 44.1210, -86.6080 |
| Nearest City | Manitowoc (84 km) |
| Impact Tier | minor |
| Timestamp | 2026-09-02T10:55:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.78f7b5d4ab65716184abdfb576959fead1c65783.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Pentwater to Manistee MI; Lake Michigan from Pentwater to Manistee MI 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued September 2 at 6:55AM EDT until September 2 at 8:30AM EDT by NWS Grand Rapids MI |
| Expires | 2026-09-02T08:30:00-04:00 |
| 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 16/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.