Right now
The most recent data we hold from NOAA arrived 4 minutes ago, and this point is not in it. We record detections, not passes: an absence is not proof that nothing is there.
Nothing else has been detected within 20 km in the last 24 hours.
This alert expired on 20 July 2026 at 23:45 UTC. It is kept here as a record.
It is the 10th strongest of the 20 detections recorded within 20 km of this point since 16 March 2026. Another comparable one was recorded here earlier the same day. 5 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued July 20 at 6:12PM CDT until July 20 at 6:45PM CDT by NWS Des Moines IA
Urban PEI: 42,745 within a heuristic 50 km radius; not unique people.
Nearby, since 16 March 2026
- May 19, 2026 · score 67 · 14.6 km
- August 13, 2026 · score 43 · 22.2 km
How we know
One source: NOAA. Not yet confirmed by a second, independent source.
Our own score for this event is 28 out of 100.
This is our versioned heuristic index, not source severity or a calibrated probability. Urban PEI does not count unique people.
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) | 28 / 100 |
| Legacy data-support index | 0.80/1 |
| Coordinates | 41.9837, -92.9510 |
| Nearest City | Marshalltown (8 km) |
| Urban exposure index (PEI) | 42.7K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-07-20T23:12:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.676b363750b1ffacc3ff8d612016c827 |
Physical priority index · v1. Heuristic priority, not calibrated probability, predictive accuracy or damage. The legacy data-support index combines assigned source support and field availability. Urban PEI is distance-weighted and does not count unique people; zero does not establish that nobody is present. Model cards.
Source and revision timeline
Source: noaa. Occurrence: 2026-07-20T23:12:00.000Z.
First archived: 2026-07-20T23:14:01.474Z. Material modification: not recorded.
Retained revisions are prospective; earlier versions may be unavailable. No revision entry does not prove that a record never changed.
Score Breakdown
Technical Details
| Event | Severe Thunderstorm Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Poweshiek, IA; Jasper, IA; Marshall, IA; Story, IA; Boone, IA; Hamilton, IA; Hardin, IA; Marshall, IA; Story, IA and 4 more areas |
| Headline | Severe Thunderstorm Warning issued July 20 at 6:12PM CDT until July 20 at 6:45PM CDT by NWS Des Moines IA |
| Expires | 2026-07-20T18:45:00-05:00 |
| SenderName | NWS Des Moines IA |
| HasExactCoords | true |
| MergedCount | 7 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.676b363750b1ffacc3ff8d612016c82794cce808.002.1","noaa_urn:oid:2.49.0.1.840.0.56f8b2fd20ac5b05df2525443dda79ba4422d1c6.001.1","noaa_urn:oid:2.49.0.1.840.0.54159d447786512a42facd4a9aab9d3dcd24016f.001.1","noaa_urn:oid:2.49.0.1.840.0.7be8fab9eae5cc0abd78c3102e08ea62d63be5d2.001.1","noaa_urn:oid:2.49.0.1.840.0.d6ef2c45322f49f6c2a26e9f7948d127f5d38f1d.002.1","noaa_urn:oid:2.49.0.1.840.0.4c1147925d5e73f12efb5165884ecc58d230474f.001.1","noaa_urn:oid:2.49.0.1.840.0.71b5c4488711632e20d3d65b72f98dc5f22087ba.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 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.
Review the area, threshold and delivery channel in your account.
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