Right now
The most recent data we hold from NOAA arrived 4 hours 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 17 May 2026 at 23:15 UTC. It is kept here as a record.
No stronger detection stands among the 20 recorded within 20 km of this point since 15 March 2026 — 2 others scored the same. Another comparable one was recorded here earlier the same day. 4 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Tornado Warning issued May 17 at 5:36PM CDT until May 17 at 6:15PM CDT by NWS Hastings NE
Urban PEI: 51,440 within a heuristic 50 km radius; not unique people.
How we know
13 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 63 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 | Critical |
| Calamity Score (ours) | 63 / 100 |
| Legacy data-support index | 0.88/1 |
| Coordinates | 41.2617, -98.0083 |
| Nearest City | Grand Island (46 km) |
| Urban exposure index (PEI) | 51.4K within 50 km |
| Impact Tier | severe |
| Timestamp | 2026-05-17T22:36:00.000Z |
| Source | https://api.weather.gov/alerts/urn:oid:2.49.0.1.840.0.65463f7e8baecf42c18562bf52b8568e46d49e8f.001.1 |
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: 2026-05-17T22:36:00.000Z.
First archived: 2026-05-17T22:44:23.838Z. 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 | Tornado Warning |
| Urgency | Immediate |
| Certainty | Observed |
| AreaDesc | Merrick, NE; Nance, NE; Polk, NE |
| Headline | Tornado Warning issued May 17 at 5:36PM CDT until May 17 at 6:15PM CDT by NWS Hastings NE |
| Expires | 2026-05-17T18:15:00-05:00 |
| SenderName | NWS Hastings NE |
| HasExactCoords | true |
| Iem TypeSummary | H |
| Iem Magnitude | 2.5 |
| Iem Unit | Inch |
| Iem City | Ashton |
| Iem County | Sherman |
| Iem State | NE |
| Iem Wfo | GID |
| MergedSources | [{"id":"iem_T_41.080_-98.380_1779055440000","source":"iem","severity":"low","severityValue":25,"timestamp":1779055440000,"latitude":41.08,"longitude":-98.38},{"id":"iem_H_41.230_-98.860_1779053700000","source":"iem","severity":"low","severityValue":25,"timestamp":1779053700000,"latitude":41.23,"longitude":-98.86},{"id":"iem_H_41.290_-98.570_1779054840000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054840000,"latitude":41.29,"longitude":-98.57},{"id":"iem_H_41.250_-98.790_1779054660000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054660000,"latitude":41.25,"longitude":-98.79},{"id":"iem_H_41.070_-98.720_1779053640000","source":"iem","severity":"low","severityValue":25,"timestamp":1779053640000,"latitude":41.07,"longitude":-98.72},{"id":"iem_H_41.260_-98.740_1779054600000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054600000,"latitude":41.26,"longitude":-98.74},{"id":"iem_H_41.210_-98.460_1779056040000","source":"iem","severity":"low","severityValue":25,"timestamp":1779056040000,"latitude":41.21,"longitude":-98.46},{"id":"iem_H_41.300_-98.570_1779054960000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054960000,"latitude":41.3,"longitude":-98.57},{"id":"iem_T_41.050_-98.570_1779054660000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054660000,"latitude":41.05,"longitude":-98.57},{"id":"iem_H_41.120_-98.550_1779054240000","source":"iem","severity":"low","severityValue":25,"timestamp":1779054240000,"latitude":41.12,"longitude":-98.55},{"id":"iem_H_41.120_-98.550_1779055860000","source":"iem","severity":"low","severityValue":25,"timestamp":1779055860000,"latitude":41.12,"longitude":-98.55},{"id":"iem_H_41.250_-98.790_1779053400000","source":"iem","severity":"low","severityValue":25,"timestamp":1779053400000,"latitude":41.25,"longitude":-98.79}] |
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.
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