This alert expired on 3 September 2026 at 19:30 UTC. It is kept here as a record.
It is one of only 3 we have recorded within 20 km of this point since 3 July 2026. The last comparable one was on 3 July 2026.
What the source measured
NOAA reported: Special Marine Warning issued September 3 at 2:33PM EDT until September 3 at 3:30PM EDT by NWS Cleveland OH
An estimated 76,541 people live within 50 km of this point.
Nearby, since 3 July 2026
- September 3, 2026 · score 37 · 16.8 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 32 out of 100, at 86 % 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) | 32 / 100 |
| Our confidence | 86% |
| Coordinates | 42.3024, -82.1523 |
| Nearest City | Chatham (12 km) |
| Population Exposed | 76.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-03T18:33:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.88740862bc2d4ea314c50361efa6b88143f83e3d.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Avon Point to Willowick OH; Willowick to Geneva-on-the Lake OH; Avon Point to Willowick OH beyond 5 nm off shoreline to US-Canadian border; St. Clair River; Harbor Beach to Port Sanilac MI; Port Sanilac to Port Huron MI; Lake Huron from Harbor Beach to Port Sanilac 5NM Off Shore to US/Canadian border; Lake Huron from Port Sanilac to Port Huron 5NM Off Shore to US/Canadian border |
| Headline | Special Marine Warning issued September 3 at 2:33PM EDT until September 3 at 3:30PM EDT by NWS Cleveland OH |
| Expires | 2026-09-03T15:30:00-04:00 |
| SenderName | NWS Cleveland OH |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.88740862bc2d4ea314c50361efa6b88143f83e3d.001.1","noaa_urn:oid:2.49.0.1.840.0.67b3ecd03cfbcf5be2e0d578ecf438416bff5294.001.1"] |
| Google News RssFeed | weather |
| Google News SourceName | CBS News |
| MergedSources | [{"id":"gnews_weather_496794_209","source":"google_news","severity":"medium","severityValue":40,"timestamp":1788458858000,"latitude":42.33,"longitude":-83.05}] |
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 Chatham?
Calamity.live data shows a weather event with CalamityScore 32/100, near Chatham (Canada), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.