This alert expired on 10 August 2026 at 09:00 UTC. It is kept here as a record.
No stronger detection stands among the 79 recorded within 20 km of this point since 31 March 2026 — 17 others scored the same. Another comparable one was recorded here earlier the same day. 2 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Flash Flood Warning issued August 10 at 12:49AM CDT until August 10 at 4:00AM CDT by NWS Chicago IL
An estimated 1,300,647 people live within 50 km of this point.
Nearby, since 31 March 2026
- July 4, 2026 · score 52 · 11.5 km
- August 11, 2026 · score 48 · 12.4 km
- July 3, 2026 · score 46 · 12.5 km
How we know
Confirmed by 4 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 90 % 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 | 90% |
| Coordinates | 41.7793, -88.6391 |
| Nearest City | DeKalb (19 km) |
| Population Exposed | 1.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-10T05:49:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.8e119d35521742d732c43bd43be2d7b1 |
Score Breakdown
Technical Details
| Event | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | La Salle, IL; Racine, WI; Walworth, WI; Grundy, IL; La Salle, IL; Livingston, IL |
| Headline | Flash Flood Warning issued August 10 at 12:49AM CDT until August 10 at 4:00AM CDT by NWS Chicago IL |
| Expires | 2026-08-10T04:00:00-05:00 |
| SenderName | NWS Chicago IL |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.8e119d35521742d732c43bd43be2d7b137b8b871.001.1","noaa_urn:oid:2.49.0.1.840.0.a7bb821c32a8eee648f34137fdb292df81262e9b.001.1","noaa_urn:oid:2.49.0.1.840.0.c2ff0c1c04c90d1c44bc5b71f447beffabcb37db.001.1"] |
| Iem TypeSummary | R |
| Iem Magnitude | 3.33 |
| Iem Unit | Inch |
| Iem City | 5 SE Ashton |
| Iem County | Lee |
| Iem State | IL |
| Iem Wfo | LOT |
| Iem Remark | Private weather station reported 3.33 inches of rain since 8:30 PM. |
| MergedSources | [{"id":"iem_D_41.740_-89.210_1786331880000","source":"iem","severity":"low","severityValue":25,"timestamp":1786331880000,"latitude":41.74,"longitude":-89.21},{"id":"iem_D_41.710_-89.240_1786330920000","source":"iem","severity":"low","severityValue":25,"timestamp":1786330920000,"latitude":41.71,"longitude":-89.24},{"id":"iem_R_41.800_-89.160_1786333800000","source":"iem","severity":"low","severityValue":25,"timestamp":1786333800000,"latitude":41.8,"longitude":-89.16}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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 DeKalb?
Calamity.live data shows a weather event with CalamityScore 52/100, near DeKalb (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.