This alert expired on 16 May 2026 at 05:00 UTC. It is kept here as a record.
It is the 5th strongest of the 28 detections recorded within 20 km of this point since 16 March 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: Severe Thunderstorm Warning issued May 15 at 11:34PM CDT until May 16 at 12:00AM CDT by NWS Des Moines IA
How we know
Confirmed by 5 independent sources, including NOAA.
Our own score for this event is 22 out of 100, at 70 % 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 | 70% |
| Coordinates | 42.7109, -91.5892 |
| Nearest City | Waterloo (66 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-16T04:34:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.74e24e6517adfd96b3bf3c69a27ceb0f |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Hamilton, IA; Hardin, IA; Delaware, IA; Crawford, WI; Grant, WI and 2 more areas |
| Headline | Severe Thunderstorm Warning issued May 15 at 11:34PM CDT until May 16 at 12:00AM CDT by NWS Des Moines IA |
| Expires | 2026-05-16T00:00:00-05:00 |
| SenderName | NWS Des Moines IA |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.74e24e6517adfd96b3bf3c69a27ceb0f83957621.001.1","noaa_urn:oid:2.49.0.1.840.0.1ff75d39faec929ea49395a38f606e6942dca3a3.001.1","noaa_urn:oid:2.49.0.1.840.0.bb4fb94d5c66976b5bd03b631d0e6e1c863d52df.001.1","noaa_urn:oid:2.49.0.1.840.0.1ec840aada8876e0c3388c896ef42b7df5a6c541.001.1","noaa_urn:oid:2.49.0.1.840.0.262df2014e3f6689e3f6c3a0a06a5f9cb5762c64.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 54 |
| Iem Unit | MPH |
| Iem City | Monona |
| Iem County | Clayton |
| Iem State | IA |
| Iem Wfo | ARX |
| MergedSources | [{"id":"iem_G_42.670_-91.920_1778902740000","source":"iem","severity":"low","severityValue":25,"timestamp":1778902740000,"latitude":42.67,"longitude":-91.92},{"id":"iem_G_42.780_-91.470_1778903640000","source":"iem","severity":"low","severityValue":25,"timestamp":1778903640000,"latitude":42.78,"longitude":-91.47},{"id":"iem_G_43.050_-91.450_1778902740000","source":"iem","severity":"low","severityValue":25,"timestamp":1778902740000,"latitude":43.05,"longitude":-91.45},{"id":"iem_G_43.050_-91.390_1778902980000","source":"iem","severity":"low","severityValue":25,"timestamp":1778902980000,"latitude":43.05,"longitude":-91.39}] |
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.