Winter Storm Warnings
December 20 2025
* WHAT...Snow expected. Total snow accumulations between 6 and 10
inches. Winds gusting as high as 60 mph.
* WHERE...Sierra Madre Range and Snowy Range.
* WHEN...From 8 PM this evening to 8 PM MST Saturday.
* IMPACTS...Travel could be very difficult. Very strong winds could
cause extensive tree damage.
* WHAT...Heavy snow. Additional snow accumulations of 8 to 16
inches. Winds gusting as high as 50 mph.
* WHERE...Salt River and Wyoming Ranges.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be very difficult including over Salt River
Pass. Blowing snow could significantly reduce visibility.
Backcountry travel is not advised.
* WHAT...Heavy snow. Additional snow accumulations between 4 to 8
inches, with higher amounts of 10 to 20 inches in southern
Yellowstone. Additional snow around Mammoth of 1 to 3 inches.
Winds may be gusting as high as 55 mph at times.
* WHERE...Yellowstone National Park.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be very difficult, especially in the
backcountry.
* WHAT...Heavy snow. Additional snow accumulations of 10 to 20
inches with amounts of 1 to 2 feet in the highest elevations. 3 to
6 inches of additional snow is expected for South Pass. Winds
could gust as high as 60 to 70 mph with locally stronger gusts
possible.
* WHERE...Wind River Mountains East and Wind River Mountains West.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be very difficult. Blowing snow could
significantly reduce visibility. The hazardous conditions could
impact travel along South Pass. Backcountry travel is not advised.
* WHAT...Heavy snow. Additional snow accumulations between 8 to 16
inches with higher elevations seeing 1 to 2 feet. Winds gusting as
high as 55 mph.
* WHERE...Absaroka Mountains and Teton and Gros Ventre Mountains.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be very difficult. The hazardous conditions
will impact travel across Teton and Togwotee Passes. Blowing and
drifting of snow is expected. Backcountry travel is not advised.
* WHAT...Snow. Additional snow accumulations of 1 to 4. Winds
gusting as high as 40 mph at times.
* WHERE...Upper Green River Basin Foothills.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be difficult. The hazardous conditions
could impact the Friday morning and evening commutes.
* ADDITIONAL DETAILS...Temperatures may warm above freezing during
the daytime Friday which would lead to a possible transition over
to a mix of rain/snow or heavy wet snow. Accumulations may be
limited during this time but slick conditions could still be
possible.
* WHAT...Snow. Additional snow accumulations of 3 to 6 inches with
lesser amounts of 2 to 4 inches across Star Valley. Winds gusting
as high as 45 mph at times.
* WHERE...Jackson Hole and Star Valley.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Travel could be difficult. The hazardous conditions
could impact the Thursday evening and Friday morning as well as
evening commutes.
* ADDITIONAL DETAILS...Additional amounts of 6 to 10 inches for
northern Jackson Valley, including around Moran Junction.
* WHAT...Southwest winds 35 to 45 mph with gusts up to 70 mph.
* WHERE...Casper Mountain, Green Mountains and Rattlesnake Range,
and Natrona County Lower Elevations.
* WHEN...Until 11 PM MST this evening.
* IMPACTS...Damaging winds may blow down trees and power lines.
Travel could be difficult, especially for high profile vehicles.
* ADDITIONAL DETAILS...Localized stronger winds up to 80 mph are
possible for wind prone locations, like Outer Drive in southern
Casper.
* WHAT...West winds 30 to 40 mph with gusts up to 60 mph.
* WHERE...Banner County, Kimball County, Northern Sioux County,
Scotts Bluff County, and Southern Sioux County.
* WHEN...Until 11 PM MST this evening.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...West winds 40 to 60 mph with gusts up to 95 mph.
* WHERE...North Laramie Range.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...West winds 35 to 45 mph with gusts up to 70 mph.
* WHERE...Niobrara County, East Laramie County, and Goshen County.
* WHEN...Until 11 PM MST this evening.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...Southwest winds 35 to 45 mph with gusts up to 75 mph
possible.
* WHERE...Ferris/Seminoe/Shirley Mountains.
* WHEN...Until 11 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...West winds 35 to 45 mph with gusts up to 75 mph.
* WHERE...Central Carbon County, Shirley Basin, Upper North Platte
River Basin, and Laramie Valley.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...West winds 30 to 50 mph with gusts up to 80 mph.
* WHERE...South Laramie Range including the Interstate 80 Summit
between Cheyenne and Laramie, and North Snowy Range Foothills
including Arlington and Elk Mountain along Interstate 80.
* WHEN...Until 11 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
* WHAT...West winds 30 to 40 mph with gusts up to 65 mph.
* WHERE...Converse County Lower Elevations, Central Laramie County,
and East Platte County.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* WHAT...West winds 35 to 55 mph with gusts up to 90 mph expected.
* WHERE...Bordeaux area along Interstate 25 between Chugwater and
Wheatland, and South Laramie Range Foothills.
* WHEN...Until 5 AM MST Saturday.
* IMPACTS...Mainly to transportation. Strong cross winds will be
hazardous to light weight or high profile vehicles, including
campers and tractor trailers.
* ADDITIONAL DETAILS...Wildfires will have the potential to spread
rapidly in these conditions.
...A PARTICULARLY DANGEROUS SITUATION FOR THE FOOTHILLS OF AND
IMMEDIATELY ADJACENT OF THE SOUTHERN LARAMIE RANGE THROUGH
LARAMIE COUNTY IS EXPECTED ON FRIDAY...
A strong wind event is ongoing, sustained winds of 40 to 55 mph
and gusts of 60 to 75+ mph, alongside dry conditions and low
humidity is creating an extreme environment conducive of
significant and rapid wildfire spread. These conditions will
continue into the early evening hours before improving later
tonight. These conditions will remain for elevations below 8000
feet along the southern Laramie Range and eastwards through most
of Laramie County.
* THIS IS A PARTICULARLY DANGEROUS SITUATION FOR THE FOOTHILLS
AND MID ELEVATIONS OF THE SOUTHERN LARAMIE RANGE.
* AFFECTED AREA...Fire weather zone 429.
* WIND...Sustained winds 40 to 55 mph with gusts in excess of 60
to 75 mph.
* HUMIDITY...RH values as low as 15 to 25%.
* IMPACTS...Conditions will be favorable for very rapid fire
spread. Avoid outdoor burning and any activity that may
produce a spark and start a wildfire.
...A PARTICULARLY DANGEROUS SITUATION FOR THE FOOTHILLS OF AND
IMMEDIATELY ADJACENT OF THE SOUTHERN LARAMIE RANGE THROUGH
LARAMIE COUNTY IS EXPECTED ON FRIDAY...
A strong wind event is ongoing, sustained winds of 40 to 55 mph
and gusts of 60 to 75+ mph, alongside dry conditions and low
humidity is creating an extreme environment conducive of
significant and rapid wildfire spread. These conditions will
continue into the early evening hours before improving later
tonight. These conditions will remain for elevations below 8000
feet along the southern Laramie Range and eastwards through most
of Laramie County.
* AFFECTED AREA...Fire weather zones 417, 418, 432, 433, 434,
435, 436, and 437.
* WIND...Sustained winds 30 to 50 mph with gusts in excess of 55
to 70 mph.
* HUMIDITY...RH values as low as 15 to 30%.
* IMPACTS...Any fires that develop will likely spread rapidly.
Outdoor burning is not recommended. Although conditions will
be borderline in some zones, a lack of significant
precipitation combined with the very high winds in the region
will create a critical fire weather environment.
