This alert expired on 2 September 2026 at 23:45 UTC. It is kept here as a record.
It is the 17th strongest of the 32 detections recorded within 20 km of this point since 4 April 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Special Marine Warning issued September 2 at 7:07PM EDT until September 2 at 7:45PM EDT by NWS Detroit/Pontiac MI
An estimated 101,455 people live within 50 km of this point.
Nearby, since 4 April 2026
- May 18, 2026 · score 43 · 9.9 km
- June 25, 2026 · score 43 · 14.2 km
- June 25, 2026 · score 43 · 17.6 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 37 out of 100, at 85 % 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) | 37 / 100 |
| Our confidence | 85% |
| Coordinates | 43.1246, -82.4285 |
| Nearest City | Sarnia (16 km) |
| Population Exposed | 101.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-02T23:07:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.1a51ccff5ca8fc93d53fe6311db472da8f189d99.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Port Sanilac to Port Huron MI; Lake Huron from Port Sanilac to Port Huron 5NM Off Shore to US/Canadian border |
| Headline | Special Marine Warning issued September 2 at 7:07PM EDT until September 2 at 7:45PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-09-02T19:45:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| Iem TypeSummary | D |
| Iem City | Palms |
| Iem County | Sanilac |
| Iem State | MI |
| Iem Wfo | DTX |
| Iem Remark | Sanilac County Dispatch reported numerous calls related to tree damage and wires downed across the northern half of the county. |
| MergedSources | [{"id":"iem_D_43.570_-82.600_1788379500000","source":"iem","severity":"low","severityValue":25,"timestamp":1788379500000,"latitude":43.57,"longitude":-82.6},{"id":"iem_M_43.270_-82.520_1788381000000","source":"iem","severity":"low","severityValue":25,"timestamp":1788381000000,"latitude":43.27,"longitude":-82.52},{"id":"iem_D_43.610_-82.770_1788379200000","source":"iem","severity":"low","severityValue":25,"timestamp":1788379200000,"latitude":43.61,"longitude":-82.77}] |
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 near Sarnia?
Calamity.live data shows a weather event with CalamityScore 37/100, near Sarnia (Canada), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.