Calamity
CriticalSevere WeatherCalamity Score: 46

Severe Weather in United States

MononaUnited StatesNOAA

Right now

The most recent data we hold from NOAA arrived 1 minute 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 18 May 2026 at 01:30 UTC. It is kept here as a record.

No stronger detection stands among the 19 recorded within 20 km of this point since 16 March 2026 — 5 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 7:59PM CDT until May 17 at 8:30PM CDT by NWS Sioux Falls SD

Nearby, since 16 March 2026

How we know

Confirmed by 2 independent sources, including NOAA.

Our own score for this event is 46 out of 100, at 65 % 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

TypeSevere Weather
SeverityCritical
Calamity Score (ours)46 / 100
Our confidence65%
Coordinates42.1615, -95.7862
Nearest CitySioux City (63 km)
Impact Tierminor
Timestamp2026-05-18T00:59:00.000Z
Sourcehttps://api.weather.gov/alerts/merged_Tornado Warning_noaa_urn:oid:2.49.0.1.840.0.3c237c0eae4e763e528bbfb5232fbf18

Score Breakdown

95
intensity
0
population
0
cascading
80
historical

Technical Details

EventTornado Warning
UrgencyImmediate
CertaintyObserved
AreaDescCherokee, IA; Plymouth, IA; Woodbury, IA; Faribault, MN; Martin, MN; Douglas, NE; Sarpy, NE; Saunders, NE and 5 more areas
HeadlineTornado Warning issued May 17 at 7:59PM CDT until May 17 at 8:30PM CDT by NWS Sioux Falls SD
Expires2026-05-17T20:30:00-05:00
SenderNameNWS Sioux Falls SD
HasExactCoordstrue
MergedCount8
MergedIds["noaa_urn:oid:2.49.0.1.840.0.3c237c0eae4e763e528bbfb5232fbf18006351f4.001.1","noaa_urn:oid:2.49.0.1.840.0.86e0c5a85aca462d6b290320b4a440c38e41b4bc.001.1","noaa_urn:oid:2.49.0.1.840.0.0e3aec2abbcda1789c14a2519486e76097c6c526.002.1","noaa_urn:oid:2.49.0.1.840.0.d862d9477362ca9ed0fe7a9448175680582ae39c.001.1","noaa_urn:oid:2.49.0.1.840.0.87c868be8c54a714558fb74eafb34e8f9ecb4559.001.1","noaa_urn:oid:2.49.0.1.840.0.32b5da177ff0cad66722f508b16a38d6ef93d853.001.1","noaa_urn:oid:2.49.0.1.840.0.65de716a8e751763ccbd0b13e31a504261dd2c13.001.1","noaa_urn:oid:2.49.0.1.840.0.90be7fe44d866482a1ba3358a7e536cdb1e5ae7d.001.1"]
Iem TypeSummaryD
Iem CityBancroft
Iem CountyCuming
Iem StateNE
Iem WfoOAX
Iem RemarkPower is out in Bancroft.
MergedSources[{"id":"iem_D_42.010_-96.570_1779062940000","source":"iem","severity":"low","severityValue":25,"timestamp":1779062940000,"latitude":42.01,"longitude":-96.57}]

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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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.