This alert expired on 11 August 2026 at 09:45 UTC. It is kept here as a record.
No stronger detection stands among the 40 recorded within 20 km of this point since 3 April 2026 — 5 others scored the same. Another comparable one was recorded here earlier the same day. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 11 at 3:49AM CDT until August 11 at 4:45AM CDT by NWS Chicago IL
An estimated 1,532,757 people live within 50 km of this point.
Nearby, since 3 April 2026
- July 3, 2026 · score 48 · 10.7 km
- August 11, 2026 · score 52 · 12.9 km
- August 10, 2026 · score 52 · 14.7 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.
Event Data
| Type | Severe weather |
| Severity | medium |
| Calamity Score (ours) | 52 / 100 |
| Our confidence | 81% |
| Coordinates | 42.3137, -88.3973 |
| Nearest City | Woodstock (4 km) |
| Population Exposed | 1.5M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-11T08:49:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.b7542ffb22971855be1e5e7949c9e09f |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Lake, IL; McHenry, IL; McHenry, IL |
| Headline | Severe Thunderstorm Warning issued August 11 at 3:49AM CDT until August 11 at 4:45AM CDT by NWS Chicago IL |
| Expires | 2026-08-11T04:45:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.b7542ffb22971855be1e5e7949c9e09ff5e701d7.001.1","noaa_urn:oid:2.49.0.1.840.0.bd3be1417cb13773b7d83c73e77d22f91901f589.002.1"] |
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 Woodstock?
Calamity.live data shows a weather event with CalamityScore 52/100, near Woodstock (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.