This alert expired on 10 August 2026 at 07:45 UTC. It is kept here as a record.
It is the 30th strongest of the 43 detections recorded within 20 km of this point since 18 May 2026. Another comparable one was recorded here earlier the same day. 9 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Special Marine Warning issued August 10 at 12:40AM CDT until August 10 at 2:45AM CDT by NWS Chicago IL
Nearby, since 18 May 2026
- May 18, 2026 · score 22 · 8.1 km
- June 12, 2026 · score 46 · 10.8 km
- June 8, 2026 · score 43 · 12.4 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 66 % 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 | 66% |
| Coordinates | 42.1544, -87.0858 |
| Nearest City | Rogers Park (51 km) |
| Impact Tier | minor |
| Timestamp | 2026-08-10T05:40:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Special Marine Warning_noaa_urn:oid:2.49.0.1.840.0.995e3e949de92fff18cd7c5fd91c6a8e |
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; St Joseph to South Haven MI; South Haven to Holland MI; Holland to Grand Haven MI; Lake Michigan from Holland to Grand Haven MI 5NM offshore to Mid Lake; Lake Michigan from South Haven to Holland MI 5NM offshore to Mid lake; Lake Michigan from St Joseph to South Haven MI 5NM offshore to Mid Lake; Wilmette Harbor to Northerly Island IL; Northerly Island to Calumet Harbor IL; Calumet Harbor IL to Gary IN; Gary to Burns Harbor IN; Burns Harbor to Michigan City IN; Lake Michigan from Wilmette Harbor to Michigan City in 5NM offshore to Mid Lake |
| Headline | Special Marine Warning issued August 10 at 12:40AM CDT until August 10 at 2:45AM CDT by NWS Chicago IL |
| Expires | 2026-08-10T02:45:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.995e3e949de92fff18cd7c5fd91c6a8edab33a37.001.1","noaa_urn:oid:2.49.0.1.840.0.1dbba129ed78bfd2c319c246a469a77970314bcd.001.1","noaa_urn:oid:2.49.0.1.840.0.8fa507a0ee85e31b9082a57882ce2a5200dc9dc4.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 1 |
| Iem Unit | Inch |
| Iem City | Vernon Hills |
| Iem County | Lake |
| Iem State | IL |
| Iem Wfo | LOT |
| Iem Remark | Trained spotter reports quarter size hail ongoing in Vernon Hills. |
| MergedSources | [{"id":"iem_H_42.240_-87.970_1786334580000","source":"iem","severity":"low","severityValue":25,"timestamp":1786334580000,"latitude":42.24,"longitude":-87.97}] |
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 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.