Moderate Extreme Weather ● Active
Dense Fog Advisory issued October 26 at 12:42AM MDT until October 26 at 12:00PM MDT by NWS Great Falls MT, United States of America
Loading live data… · Marker positions are approximate; severity is labelled in each popup. Sources: USGS, GDACS, NASA EONET, NOAA/NWS, EMSC.
* WHAT...Visibility one quarter mile or less in dense fog.
* WHERE...Canyon Ferry Area, Elkhorn and Boulder Mountains,
Beaverhead and Western Madison below 6000ft, Gallatin Valley,
Gallatin and Madison County Mountains and Centennial Mountains,
Madison River Valley, Missouri Headwaters, and Northwest Beaverhead
County.
* WHEN...Until noon MDT today.
* IMPACTS...Low visibility could make driving conditions hazardous.
Measurements
| Coordinates | 39.9645, -100.8105 |
|---|---|
| Region | Elkhorn and Boulder Mountains; Canyon Ferry Area; Missouri Headwaters; Madison River Valley; Gallatin Valley; Northwest Beaverhead County; Beaverhead and W |
| Location Precision | country |
| Issuing Authority | United States of America — us-noaa-nws-en |
| Cap Urgency | Expected |
| Cap Certainty | Likely |
| Cap Expires | 2026-10-26T12:00:00-06:00 |
Official source
Warnings courtesy of the issuing national meteorological service, via the WMO Alert Hub.
This is an official warning issued by the authority named above. Follow its instructions and those of your local emergency services.
Severity as published by WMO Alert Hub (national weather services).
View original reportThis event as JSON · API and licence
Source updated 1 hour ago (Oct 26, 2026 06:43 UTC) · we last heard from WMO Alert Hub (national weather services) 18 seconds ago
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About this location
The agency did not publish coordinates for this warning. The pin is the centre of the country, not the location of the event — read the area name, not the map, for where it applies.
Area as the agency stated it: Elkhorn and Boulder Mountains; Canyon Ferry Area; Missouri Headwaters; Madison River Valley; Gallatin Valley; Northwest Beaverhead County; Beaverhead and W
Official authorities in United States
If you are there, these are the bodies whose instructions apply. This site is not an emergency service and does not issue warnings.
More for United States →What to do
Follow the instructions issued by WMO Alert Hub (national weather services) and your local emergency services. The guidance below is background.
When thunder roars, go indoors — lightning risk outdoors, in vehicles, and first aid for strike victims.
Open Lightning Safety Guide →Earlier extreme weather events in United States
Severe and extreme events of the same kind, before this one. Listed for scale, not because they are connected to it.
Nearby & related events
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