This alert expired on 11 August 2026 at 10:00 UTC. It is kept here as a record.
No stronger detection stands among the 20 recorded within 20 km of this point since 10 June 2026 — 13 others scored the same. The last comparable one was on 10 August 2026. 3 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued August 11 at 3:34AM CDT until August 11 at 5:00AM CDT by NWS Chicago IL
An estimated 5,415,746 people live within 50 km of this point.
Nearby, since 10 June 2026
- July 3, 2026 · score 46 · 2.4 km
- August 10, 2026 · score 52 · 6.0 km
- June 11, 2026 · score 46 · 7.1 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 52 out of 100, at 82 % 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) | 52 / 100 |
| Our confidence | 82% |
| Coordinates | 42.2650, -87.5440 |
| Nearest City | Highland Park (23 km) |
| Population Exposed | 5.4M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-11T08:34:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.e92348837856505423e8f5c325b2619e7299f4aa.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Winthrop Harbor to Wilmette Harbor IL; Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake; Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued August 11 at 3:34AM CDT until August 11 at 5:00AM CDT by NWS Chicago IL |
| Expires | 2026-08-11T05:00:00-05:00 |
| SenderName | NWS Chicago IL |
| 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 near Highland Park?
Calamity.live data shows a weather event with CalamityScore 52/100, near Highland Park (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.