Right now
The most recent data we hold from NOAA arrived 46 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 28 June 2026 at 00:30 UTC. It is kept here as a record.
It is the strongest of the 14 detections recorded within 20 km of this point since 3 April 2026. 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: Severe Thunderstorm Warning issued June 27 at 5:55PM MDT until June 27 at 6:30PM MDT by NWS Riverton WY
Urban PEI: 17,873 within a heuristic 50 km radius; not unique people.
How we know
7 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 34 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) | 34 / 100 |
| Legacy data-support index | 0.89/1 |
| Coordinates | 44.3949, -106.8648 |
| Nearest City | Sheridan (46 km) |
| Urban exposure index (PEI) | 17.9K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-27T23:55:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.d7ba65b1d619199ca8820cec5704a380 |
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: 2026-06-27T23:55:00.000Z.
First archived: 2026-06-28T00:19:52.640Z. 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 | Big Horn, WY; Johnson, WY; Washakie, WY; Johnson, WY |
| Headline | Severe Thunderstorm Warning issued June 27 at 5:55PM MDT until June 27 at 6:30PM MDT by NWS Riverton WY |
| Expires | 2026-06-27T18:30:00-06:00 |
| SenderName | NWS Riverton WY |
| HasExactCoords | true |
| MergedCount | 2 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.d7ba65b1d619199ca8820cec5704a380e5695c99.001.1","noaa_urn:oid:2.49.0.1.840.0.48e2ce6e5037feb410fa81da8f6a5da041503838.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 55 |
| Iem Unit | MPH |
| Iem City | 7 NE Buffalo |
| Iem County | Johnson |
| Iem State | WY |
| Iem Wfo | RIW |
| Iem Remark | Mesonet station DW9955 Buffalo 2 (CWOP). |
| MergedSources | [{"id":"iem_H_44.720_-106.720_1782586800000","source":"iem","severity":"low","severityValue":25,"timestamp":1782586800000,"latitude":44.72,"longitude":-106.72},{"id":"iem_H_44.600_-106.360_1782590400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782590400000,"latitude":44.6,"longitude":-106.36},{"id":"iem_G_44.020_-106.640_1782601680000","source":"iem","severity":"low","severityValue":25,"timestamp":1782601680000,"latitude":44.02,"longitude":-106.64},{"id":"iem_G_44.200_-106.260_1782602400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782602400000,"latitude":44.2,"longitude":-106.26},{"id":"iem_G_44.320_-106.710_1782602160000","source":"iem","severity":"low","severityValue":25,"timestamp":1782602160000,"latitude":44.32,"longitude":-106.71},{"id":"iem_G_44.420_-106.590_1782603000000","source":"iem","severity":"low","severityValue":25,"timestamp":1782603000000,"latitude":44.42,"longitude":-106.59}] |
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.
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