This alert expired on 1 July 2026 at 20:00 UTC. It is kept here as a record.
No stronger detection stands among the 11 recorded within 20 km of this point since 4 April 2026 — 3 others scored the same. Another comparable one was recorded here earlier the same day. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued July 1 at 3:35PM EDT until July 1 at 4:00PM EDT by NWS Detroit/Pontiac MI
Nearby, since 4 April 2026
- June 10, 2026 · score 16 · 6.4 km
- September 2, 2026 · score 16 · 8.7 km
- June 16, 2026 · score 22 · 15.1 km
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 70 % 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 | 70% |
| Coordinates | 43.5714, -82.3571 |
| Nearest City | Sarnia (66 km) |
| Impact Tier | minor |
| Timestamp | 2026-07-01T19:35:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.91427bfe5d9a345ddb7d9b817de610416e890f28.002.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Harbor Beach to Port Sanilac MI; Lake Huron from Port Austin to Harbor Beach 5NM Off Shore to the US/Canadian border; 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 July 1 at 3:35PM EDT until July 1 at 4:00PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-07-01T16:00:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| Iem TypeSummary | M |
| Iem Magnitude | 40 |
| Iem Unit | mph |
| Iem City | 1 E Harbor Beach |
| Iem County | Huron |
| Iem State | MI |
| Iem Wfo | DTX |
| Iem Remark | Measured at HRBM4. |
| MergedSources | [{"id":"iem_M_43.940_-82.720_1782932100000","source":"iem","severity":"low","severityValue":25,"timestamp":1782932100000,"latitude":43.94,"longitude":-82.72},{"id":"iem_G_43.780_-82.980_1782932460000","source":"iem","severity":"low","severityValue":25,"timestamp":1782932460000,"latitude":43.78,"longitude":-82.98},{"id":"iem_M_43.850_-82.640_1782932400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782932400000,"latitude":43.85,"longitude":-82.64}] |
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 (Canada), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.