This alert expired on 11 August 2026 at 10:00 UTC. It is kept here as a record.
No stronger detection stands among the 28 recorded within 20 km of this point since 8 June 2026 — 13 others scored the same. Another comparable one was recorded here earlier the same day. 6 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued August 11 at 4:07AM CDT until August 11 at 5:00AM CDT by NWS Chicago IL
An estimated 1,692,079 people live within 50 km of this point.
Nearby, since 8 June 2026
- July 27, 2026 · score 52 · 2.5 km
- July 27, 2026 · score 52 · 6.5 km
- August 10, 2026 · score 52 · 8.1 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 81 % 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 | 81% |
| Coordinates | 42.2489, -87.3556 |
| Nearest City | Wilmette (36 km) |
| Population Exposed | 1.7M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-11T09:07:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.3e7a1def68be8fe9d0b6d252b2583b792d3bcaca.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 4:07AM 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 in this area?
Calamity.live data shows a weather event with CalamityScore 52/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.