Right now
The most recent data we hold from NOAA arrived 3 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 June 2026 at 23:00 UTC. It is kept here as a record.
No stronger detection stands among the 11 recorded within 20 km of this point since 11 April 2026 — 4 others scored the same. Another comparable one was recorded here earlier the same day. 7 more were recorded here in the fortnight before it.
What the source measured
NOAA reported: Severe Thunderstorm Warning issued June 20 at 4:50PM MDT until June 20 at 5:00PM MDT by NWS Riverton WY
Nearby, since 11 April 2026
- July 7, 2026 · score 22 · 6.3 km
- June 20, 2026 · score 22 · 16.3 km
How we know
3 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 22 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) | 22 / 100 |
| Legacy data-support index | 0.69/1 |
| Coordinates | 43.5948, -106.0830 |
| Nearest City | Casper (83 km) |
| Urban exposure index (PEI) | 0 within 50 km |
| Impact Tier | minor |
| Timestamp | 2026-06-20T22:50:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Severe Thunderstorm Warning_noaa_urn:oid:2.49.0.1.840.0.38c4cfef2e1ffbcabaea5fb15ea3da00 |
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: 2026-06-20T22:50:00.000Z.
First archived: 2026-06-20T22:56:01.680Z. 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; Converse, WY; Platte, WY and 2 more areas |
| Headline | Severe Thunderstorm Warning issued June 20 at 4:50PM MDT until June 20 at 5:00PM MDT by NWS Riverton WY |
| Expires | 2026-06-20T17:00:00-06:00 |
| SenderName | NWS Riverton WY |
| HasExactCoords | true |
| MergedCount | 5 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.38c4cfef2e1ffbcabaea5fb15ea3da00f4ad08c5.001.1","noaa_urn:oid:2.49.0.1.840.0.c6317473ddcc9f078821cb9a071c5a87b883fa29.001.1","noaa_urn:oid:2.49.0.1.840.0.1f7e9c672917f9ee95eb8aaad7d7ee17718f4679.001.1","noaa_urn:oid:2.49.0.1.840.0.a1eea18511e4ea119bb59d8434c83f77ced498db.001.1","noaa_urn:oid:2.49.0.1.840.0.571236066ab40663bc5ef2d6b4a0ef5d27efd238.001.1"] |
| Iem TypeSummary | G |
| Iem Magnitude | 59 |
| Iem Unit | MPH |
| Iem City | 17 SSW Midwest |
| Iem County | Natrona |
| Iem State | WY |
| Iem Wfo | RIW |
| Iem Remark | Mesonet station PC576 Horse Ranch Creek (PC). |
| MergedSources | [{"id":"iem_G_43.120_-106.340_1781992560000","source":"iem","severity":"low","severityValue":25,"timestamp":1781992560000,"latitude":43.12,"longitude":-106.34},{"id":"iem_G_43.180_-106.340_1781992200000","source":"iem","severity":"low","severityValue":25,"timestamp":1781992200000,"latitude":43.18,"longitude":-106.34}] |
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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