This alert expired on 12 August 2026 at 23:00 UTC. It is kept here as a record.
It is the 2nd strongest of the 24 detections recorded within 20 km of this point since 12 March 2026. Another comparable one was recorded here earlier the same day. One more was recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued August 12 at 4:55PM CDT until August 12 at 6:00PM CDT by NWS St Louis MO
An estimated 59,289 people live within 50 km of this point.
Nearby, since 12 March 2026
- August 12, 2026 · score 39 · 10.3 km
- March 16, 2026 · score 58 · 15.6 km
- August 12, 2026 · score 39 · 18.7 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 39 out of 100, at 78 % 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) | 39 / 100 |
| Our confidence | 78% |
| Coordinates | 38.0590, -88.9369 |
| Nearest City | Mount Vernon (29 km) |
| Population Exposed | 59.3K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-08-12T21:55:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.1d85bf318e1c774997e5b77f46a76ed7 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Franklin, MO; Gasconade, MO; Perry, MO; Maries, MO; Phelps, MO and 6 more areas |
| Headline | Severe Thunderstorm Warning issued August 12 at 4:55PM CDT until August 12 at 6:00PM CDT by NWS St Louis MO |
| Expires | 2026-08-12T18:00:00-05:00 |
| SenderName | NWS St Louis MO |
| HasExactCoords | true |
| MergedCount | 10 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.1d85bf318e1c774997e5b77f46a76ed73deacfdf.001.1","noaa_urn:oid:2.49.0.1.840.0.2660a5c155d4ba89cb6373cb3d01357a7e50f0c1.001.1","noaa_urn:oid:2.49.0.1.840.0.acbc29fa34713d27f7e665d37e58519c16976325.001.1","noaa_urn:oid:2.49.0.1.840.0.a61a80d993e5f73eb3cca4050f5bd700c0bc35ca.001.1","noaa_urn:oid:2.49.0.1.840.0.cca52938e411cec7111896200bee1254f5b0603b.001.1","noaa_urn:oid:2.49.0.1.840.0.85831cf14027c045abd3f051c89417009194504e.002.1","noaa_urn:oid:2.49.0.1.840.0.0b624d11f6cbaf86bfb23c13ba93cf9f2a07536e.001.1","noaa_urn:oid:2.49.0.1.840.0.e78efe67ee37d6996bf30d93a5a9856aa461ff7c.001.1","noaa_urn:oid:2.49.0.1.840.0.da8119d3ed1cd241aa5badecae3452ecea8c67f3.001.1","noaa_urn:oid:2.49.0.1.840.0.08854df9fdc7624fc1d9116ecbf85af6724f291b.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 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 Mount Vernon?
Calamity.live data shows a weather event with CalamityScore 39/100, near Mount Vernon (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.