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 27 June 2026 at 23:30 UTC. It is kept here as a record.
It is the 5th strongest of the 8 detections recorded within 20 km of this point since 27 June 2026.
What the source measured
NOAA reported: Flash Flood Warning issued June 27 at 2:28PM MDT until June 27 at 5:30PM MDT by NWS Billings MT
Urban PEI: 117,116 within a heuristic 50 km radius; not unique people.
Nearby, since 27 June 2026
- June 27, 2026 · score 43 · 2.2 km
- July 16, 2026 · score 43 · 7.9 km
How we know
4 recorded sources include NOAA; independence is not established by this count.
Our own score for this event is 37 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) | 37 / 100 |
| Legacy data-support index | 0.88/1 |
| Coordinates | 45.5971, -107.9892 |
| Nearest City | Billings (45 km) |
| Urban exposure index (PEI) | 117.1K within 50 km |
| Impact Tier | significant |
| Timestamp | 2026-06-27T20:28:00.000Z |
| Source | https://api.weather.gov/alerts/merged_Flash Flood Warning_noaa_urn:oid:2.49.0.1.840.0.6a3c3f269aa4fc2aa610e083110096b2 |
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: 2026-06-27T20:28:00.000Z.
First archived: 2026-06-27T20:58:45.346Z. 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 | Flash Flood Warning |
| Urgency | Immediate |
| Certainty | Likely |
| AreaDesc | Rosebud, MT; Yellowstone, MT; Stillwater, MT |
| Headline | Flash Flood Warning issued June 27 at 2:28PM MDT until June 27 at 5:30PM MDT by NWS Billings MT |
| Expires | 2026-06-27T17:30:00-06:00 |
| SenderName | NWS Billings MT |
| HasExactCoords | true |
| MergedCount | 3 |
| MergedIds | ["noaa_urn:oid:2.49.0.1.840.0.6a3c3f269aa4fc2aa610e083110096b2bbeaebd2.001.1","noaa_urn:oid:2.49.0.1.840.0.fd93caaed470cd262ac71865289ae5b23284e48a.001.1","noaa_urn:oid:2.49.0.1.840.0.8c6b844089c937649bd67f3801aca94c5541af11.001.1"] |
| Iem TypeSummary | H |
| Iem Magnitude | 0.88 |
| Iem Unit | Inch |
| Iem City | Laurel |
| Iem County | Yellowstone |
| Iem State | MT |
| Iem Wfo | BYZ |
| Iem Remark | Dime to nickel sized hail. Rainfall filling curbs. |
| MergedSources | [{"id":"iem_H_45.750_-108.570_1782590400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782590400000,"latitude":45.75,"longitude":-108.57},{"id":"iem_H_45.680_-108.770_1782590400000","source":"iem","severity":"low","severityValue":25,"timestamp":1782590400000,"latitude":45.68,"longitude":-108.77},{"id":"iem_H_45.680_-108.780_1782588900000","source":"iem","severity":"low","severityValue":25,"timestamp":1782588900000,"latitude":45.68,"longitude":-108.78}] |
Safety Information
During flooding: never walk, swim, or drive through floodwaters. Six inches of moving water can knock you down, and one foot of water can sweep away a vehicle. Move to higher ground if waters rise. After flooding, avoid contact with floodwater which may contain sewage, chemicals, or debris. Follow local emergency service guidance.
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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