This is an archived forecast, related to an incident on this day

Backcountry Avalanche Forecast - Tetons
Issued: Saturday, December 20, 2025 - 6:40AM
Expires: Sunday, December 21, 2025 - 12:00AM
Author: Michael Rheam

THE BOTTOM LINE

Dangerous avalanche conditions exist in the backcountry.  Skiers and riders have the potential to trigger slab avalanches in steep terrain above 8000 feet on a variety of aspects. Avoid areas with obvious signs of wind loading however any steep terrain is suspect and requires snowpack evaluation. Shooting cracks will be a strong warning sign that an area or slope is unstable. 

Avalanche Forecast

Avalanche Danger
Saturday, December 20, 2025
10,500' - 9,000': 3 - Considerable
9,000' - 7,500': 3 - Considerable
7,500' - 6,000': 1 - Low

Avalanche Problems (1)

Problem #1: Wind Slab

All Aspects
10,500' - 9,000' and 9,000' - 7,500'
Likelihood: Likely
Size
Small (D1) to  Large (D2)

Approximately 2-3  feet of heavy snow  has fallen since Tuesday. This snowfall was accompanied by very strong southwest to northwest winds with gusts of 60-90 mph each day and lies upon hard and slick crusts on all aspects. Yesterday natural and human triggered slides were reported including an avalanche on Teton Pass that impacted traffic.  Backcountry travellers can easily trigger hard or soft slab avalanches today that could fail on the crusts or on density breaks within the recent snow with depths to 3 feet. 

The old weak snow buried in early November is not expected to be active at this time and will continue to be monitored. 

Forecast Discussion

Colder temperatures and a break from precipitation will have made the newly formed wind slabs that lie throughout the backcountry less sensitive than they were during yesterday's rapid loading. Although less sensitive, they will still be susceptible to failure, particularly in and around cliff areas as these areas are generally steeper and also recieved extensive loading.  Activity at and near the Jackson Hole Mountain Resort yesterday occurred on a density break a few inches above the hard rain crusts. Avalanches at low elevations remain unlikely due to low snow depths. The rain and rime crust that formed on December 10th and was buried on the 16th  is a problem layer that is widespread throughout all elevations and aspects.  This layer demands respect and will be followed through future storms. 

Mountain Weather

Yesterday, mountain temperatures rose into the upper 20s and low 30s, with above freezing temperatures at low elevations. Potent winds continued blowing in the upper 20s and 30s, with high ridgelines blowing in the 40s and 50s from the W and SW. Mid and upper elevation mountains picked up 5-8” with the southern Salt and Wyoming Ranges receiving less. At lower elevations, much of this fell as sleet and rain, with some places picking up a couple inches.

Overnight, snow showers slowly faded with an additional inch or two of snow trickling in. Temperatures have started to drop, descending into the teens. Winds have been declining, blowing in the teens and 20s from the W.

Today, the weather will clear out gradually if it hasn’t already, with scattered clouds by the end of the day. Mountain temperatures will start in the single digits and climb into the teens. Wind will blow from the W and SW in the teens and gusts in the 20s to 30s. Active weather is forecasted to resume tonight.