This alert expired on 18 May 2026 at 22:30 UTC. It is kept here as a record.
No stronger detection stands among the 19 recorded within 20 km of this point since 4 April 2026 — 6 others scored the same. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued May 18 at 6:07PM EDT until May 18 at 6:30PM EDT by NWS Detroit/Pontiac MI
An estimated 101,455 people live within 50 km of this point.
Nearby, since 4 April 2026
- June 25, 2026 · score 43 · 10.5 km
- July 21, 2026 · score 43 · 12.1 km
- June 25, 2026 · score 43 · 13.2 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 43 out of 100, at 79 % confidence.
The score is ours, computed from intensity, exposed population and local history — not the source’s.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 43 / 100 |
| Our confidence | 79% |
| Coordinates | 43.1025, -82.5469 |
| Nearest City | Port Huron (18 km) |
| Population Exposed | 101.5K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-18T22:07:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.7065bc164c52349b94937575a535421c |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | St. Clair, MI; Sanilac, MI |
| Headline | Severe Thunderstorm Warning issued May 18 at 6:07PM EDT until May 18 at 6:30PM EDT by NWS Detroit/Pontiac MI |
| Expires | 2026-05-18T18:30:00-04:00 |
| SenderName | NWS Detroit/Pontiac MI |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.7065bc164c52349b94937575a535421cc3d52d1b.002.1","noaa_urn:oid:2.49.0.1.840.0.0a5f9d3e15030f1bdee82eef90b8cdbb07c0a7cc.001.1"] |
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 10 February 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 Port Huron?
Calamity.live data shows a weather event with CalamityScore 43/100, near Port Huron (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.