This alert expired on 5 September 2026 at 05:00 UTC. It is kept here as a record.
It is the 15th strongest of the 23 detections recorded within 20 km of this point since 10 June 2026. Another comparable one was recorded here earlier the same day.
What the source measured
NOAA reported: Special Marine Warning issued September 4 at 10:39PM CDT until September 5 at 12:00AM CDT by NWS Chicago IL
An estimated 5,472,114 people live within 50 km of this point.
Nearby, since 10 June 2026
- August 11, 2026 · score 52 · 1.0 km
- July 3, 2026 · score 46 · 1.9 km
- August 10, 2026 · score 52 · 5.1 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 46 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 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) | 46 / 100 |
| Our confidence | 82% |
| Coordinates | 42.2579, -87.5365 |
| Nearest City | Highland Park (23 km) |
| Population Exposed | 5.5M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-09-05T03:39:00.000Z |
| Source | https://api.weather.gov/alerts/urn%3Aoid%3A2.49.0.1.840.0.752b3278be0ab24a8905b6f9f15b9ddd7cd50f30.001.1 |
Score Breakdown
Technical Details
| Event | Special Marine Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Winthrop Harbor to Wilmette Harbor IL; Wilmette Harbor to Northerly Island 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; Winthrop Harbor to Wilmette Harbor IL; Lake Michigan from Winthrop Harbor to Wilmette Harbor IL 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued September 4 at 10:39PM CDT until September 5 at 12:00AM CDT by NWS Chicago IL |
| Expires | 2026-09-05T00:00:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.752b3278be0ab24a8905b6f9f15b9ddd7cd50f30.001.1","noaa_urn:oid:2.49.0.1.840.0.2eab3fa678944a15f6f4e9d3f2fc6ebc54ace862.001.1"] |
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 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 46/100, near Highland Park (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.