Right now
The most recent data we hold from NOAA arrived 5 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
3 other detections within 20 km in the last 24 hours, the nearest <1 km from here.
This alert expired on 16 May 2026 at 06:00 UTC. It is kept here as a record.
It is the 66th strongest of the 246 detections recorded within 20 km of this point since 10 March 2026. 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 Watch issued May 15 at 11:09PM CDT until May 16 at 1:00AM CDT by NWS Des Moines IA
An estimated 181,553 people live within 50 km of this point.
Nearby, since 10 March 2026
- September 6, 2026 · score 37 · 0.0 km
- September 2, 2026 · score 37 · 0.0 km
- September 1, 2026 · score 37 · 0.0 km
How we know
Confirmed by 2 independent sources, including NOAA.
Our own score for this event is 43 out of 100, at 85 % 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) | 43 / 100 |
| Our confidence | 85% |
| Coordinates | 42.0000, -93.2000 |
| Nearest City | Marshalltown (25 km) |
| Population Exposed | 181.6K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-05-16T04:09:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Watch_noaa_urn:oid:2.49.0.1.840.0.ac0f174c22b073dca46d15e6a8647ea0 |
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Watch |
| Urgency | Future |
| Certainty | Possible |
| AreaDesc | Adair, IA; Adams, IA; Audubon, IA; Black Hawk, IA; Boone, IA; Bremer, IA; Butler, IA; Calhoun, IA; Carroll, IA; Cass, IA; Clarke, IA; Crawford, IA; Dallas, IA; Franklin, IA; Greene, IA; Grundy, IA; Guthrie, IA; Hamilton, IA; Hardin, IA; Jasper, IA; Lucas, IA; Madison, IA; Mahaska, IA; Marion, IA; Marshall, IA; Monroe, IA; Polk, IA; Poweshiek, IA; Story, IA; Tama, IA; Taylor, IA; Union, IA; Wapello, IA; Warren, IA; Webster, IA; Wright, IA; Allamakee, IA; Chickasaw, IA; Clayton, IA; Fayette, IA; Floyd, IA; Howard, IA; Mitchell, IA; Winneshiek, IA; Fremont, IA; Harrison, IA; Mills, IA; Monona, IA; Montgomery, IA; Page, IA; Pottawattamie, IA; Shelby, IA; Burt, NE; Butler, NE; Cass, NE; Dodge, NE; Douglas, NE; Lancaster, NE; Otoe, NE; Saline, NE; Sarpy, NE; Saunders, NE; Seward, NE; Washington, NE |
| Headline | Severe Thunderstorm Watch issued May 15 at 11:09PM CDT until May 16 at 1:00AM CDT by NWS Des Moines IA |
| Expires | 2026-05-16T01:00:00-05:00 |
| SenderName | NWS Des Moines IA |
| HasExactCoords | false |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.ac0f174c22b073dca46d15e6a8647ea073ac3757.002.1","noaa_urn:oid:2.49.0.1.840.0.f9823b32347a20737b868cce1294d0a26a8f8a28.003.1","noaa_urn:oid:2.49.0.1.840.0.b863fe2b4358edf8bb9dd3985f6f20a74f522fa0.003.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 64 |
| Iem Unit | MPH |
| Iem City | 3 S Iowa Falls |
| Iem County | Hardin |
| Iem State | IA |
| Iem Wfo | DMX |
| Iem Remark | PEAK GUST REPORTED AT IOWA FALLS AIRPORT. |
| MergedSources | [{"id":"iem_G_42.470_-93.270_1778901000000","source":"iem","severity":"low","severityValue":25,"timestamp":1778901000000,"latitude":42.47,"longitude":-93.27}] |
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 near Marshalltown?
Calamity.live data shows a weather event with CalamityScore 43/100, near Marshalltown (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.