This alert expired on 18 May 2026 at 02:00 UTC. It is kept here as a record.
It is the 6th strongest of the 44 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: Tornado Warning issued May 17 at 8:26PM CDT until May 17 at 9:00PM CDT by NWS Omaha/Valley NE
Nearby, since 16 March 2026
- May 16, 2026 · score 22 · 6.2 km
- June 1, 2026 · score 22 · 10.3 km
- June 1, 2026 · score 22 · 14.7 km
How we know
Confirmed by 5 independent sources, including NOAA.
Our own score for this event is 46 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 | Critical |
| Calamity Score (ours) | 46 / 100 |
| Our confidence | 70% |
| Coordinates | 41.7707, -95.8111 |
| Nearest City | Council Bluffs (57 km) |
| Impact Tier | minor |
| Timestamp | 2026-05-18T01:26:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Tornado Warning_noaa_urn:oid:2.49.0.1.840.0.0eb18dea17ec70590f1c5e3c8477f68c |
Score Breakdown
Technical Details
| Event | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Cass, NE; Otoe, NE; Marshall, KS; Washington, KS; Harrison, IA; Pottawattamie, IA; Washington, NE and 5 more areas |
| Headline | Tornado Warning issued May 17 at 8:26PM CDT until May 17 at 9:00PM CDT by NWS Omaha/Valley NE |
| Expires | 2026-05-17T21:00:00-05:00 |
| SenderName | NWS Omaha/Valley NE |
| HasExactCoords | true |
| MergedCount | 8 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.0eb18dea17ec70590f1c5e3c8477f68c01389e24.002.1","noaa_urn:oid:2.49.0.1.840.0.6019b06821abce932087993609a3cd9777223816.001.1","noaa_urn:oid:2.49.0.1.840.0.4bf51aa878095e41acefdb9b29585e4eee8a77d9.001.1","noaa_urn:oid:2.49.0.1.840.0.3c4097c19049c4a931ff98fa80ee6b25ec872229.001.1","noaa_urn:oid:2.49.0.1.840.0.5d9dd682b6baf1279c65a33ef0e0b51e69780f93.001.1","noaa_urn:oid:2.49.0.1.840.0.0f98d52b46fdeb4d7a8c815a4ecbc32cd253b249.001.1","noaa_urn:oid:2.49.0.1.840.0.5584cde4bba21d1e4e2bf68b08976b99df0ae4e8.001.1","noaa_urn:oid:2.49.0.1.840.0.777d75d204dde467496bcf2d86d9624622c8f676.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 58 |
| Iem Unit | MPH |
| Iem City | 2 ESE Walthill |
| Iem County | Thurston |
| Iem State | NE |
| Iem Wfo | OAX |
| Iem Remark | Personal Weather Station. |
| MergedSources | [{"id":"iem_D_42.010_-96.570_1779062940000","source":"iem","severity":"low","severityValue":25,"timestamp":1779062940000,"latitude":42.01,"longitude":-96.57},{"id":"iem_G_42.190_-95.900_1779065280000","source":"iem","severity":"low","severityValue":25,"timestamp":1779065280000,"latitude":42.19,"longitude":-95.9},{"id":"iem_G_42.130_-96.420_1779064080000","source":"iem","severity":"low","severityValue":25,"timestamp":1779064080000,"latitude":42.13,"longitude":-96.42},{"id":"iem_G_42.140_-96.460_1779064200000","source":"iem","severity":"low","severityValue":25,"timestamp":1779064200000,"latitude":42.14,"longitude":-96.46}] |
Safety Information
If a tornado warning is issued: go to a basement or an interior room on the lowest floor, away from windows. A vehicle and a mobile home are not shelter. Cover your head and neck. Wait for the official all-clear before going outside, and watch for downed power lines and gas leaks afterwards.
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 46/100 (United States), based on data from noaa. Source: Calamity.live, a platform aggregating real-time data from 185 scientific monitoring sources.