This alert expired on 20 May 2026 at 01:00 UTC. It is kept here as a record.
It is the 5th strongest of the 66 detections recorded within 20 km of this point since 15 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 May 19 at 8:40PM EDT until May 19 at 9:00PM EDT by NWS Wilmington OH
An estimated 1,335,280 people live within 50 km of this point.
Nearby, since 15 March 2026
- August 11, 2026 · score 76 · 1.6 km
- August 16, 2026 · score 52 · 3.7 km
- May 20, 2026 · score 52 · 4.1 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 52 out of 100, at 86 % 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 | 86% |
| Coordinates | 39.9291, -83.3042 |
| Nearest City | Hilliard (17 km) |
| Population Exposed | 1.3M within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-20T00:40:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.53d4861d7cc10cc1dcc0ec8bc73dd42e |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Clark, OH; Fayette, OH; Greene, OH; Madison, OH; Fayette, OH; Franklin, OH; Madison, OH; Pickaway, OH; Delaware, OH; Franklin, OH; Licking, OH; Madison, OH; Union, OH |
| Headline | Severe Thunderstorm Warning issued May 19 at 8:40PM EDT until May 19 at 9:00PM EDT by NWS Wilmington OH |
| Expires | 2026-05-19T21:00:00-04:00 |
| SenderName | NWS Wilmington OH |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.53d4861d7cc10cc1dcc0ec8bc73dd42e7e4efc05.002.1","noaa_urn:oid:2.49.0.1.840.0.f69eb45a66cadfd8d21f25fba73085579b0fcdce.001.1","noaa_urn:oid:2.49.0.1.840.0.6afee34c54afc7501978698aef8e37f717b74ac5.001.1"] |
| Iem TypeSummary | D |
| Iem City | Bellbrook |
| Iem County | Greene |
| Iem State | OH |
| Iem Wfo | ILN |
| Iem Remark | Top 20 feet of a very large tree down. |
| MergedSources | [{"id":"iem_D_39.640_-84.070_1779235980000","source":"iem","severity":"low","severityValue":25,"timestamp":1779235980000,"latitude":39.64,"longitude":-84.07}] |
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.
Calamity.live data shows a weather event with CalamityScore 52/100, near Hilliard (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 188 scientific monitoring sources.