Avalanche forecast

Salt Lake

Issued Dec 21, 2022valid to Dec 22, 2022Utah Avalanche Center

Avalanche danger

Alpine
Treeline
Below treeline

Out of date — this forecast expired 4 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Due to extremely high winds and new snow the avalanche danger will rise to CONSIDERABLE on all aspects at upper elevations and MODERATE on all aspects at mid-elevations by the end of the day. Watch for and avoid any freshly formed wind drifts on all upper and mid-elevation slopes. There is also a MODERATE danger at mid-elevations and low elevations northwest-north-northeast-east because of a persistent weak layer buried 1-4' deep.

The avalanche danger is LOW on low-elevation slopes facing west and southerly directions.

Any avalanche triggered within the wind-drifted snow has the potential to step down into deeper weak layers in the snowpack, creating a very large and dangerous avalanche.

Avalanche problems

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
3
There is weak, sugary faceted snow (a persistent weak layer, or PWL) buried 1-4' deep on almost all aspects and elevations throughout the Wasatch Range. Avalanches on this layer are most likely on slopes facing northwest-north-east-southeast.

Today, the likelihood will be especially prominent on any slopes that receive the additional weight of wind-drifted snow. For the snowpack, when the winds drift snow, it's the same as if snow is falling out of the sky. The snowpack doesn't care where the snow comes from, it feels the added weight. So, on northerly-facing slopes, these winds have added snow and weight, and stress to the persistent weak layer. Outside northerly-facing terrain, with the additional load of wind-drifted snow, we may begin to see activity on aspects and elevations that have been quiet over the last few days.

Avalanches are unlikely on solar aspects west through south where there haven't been any reported avalanches on this layer. The easiest way to avoid any avalanche is to go on slopes less than 30 degrees with nothing steeper above. Read about slope selection HERE.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Likely
Size
3
Winds are increasing drastically throughout the day, hitting speeds over 100 mph by this evening. With such dramatic wind speeds and soft snow available for transport you are likely to find sensitive slabs of wind-drifted snow on all upper-elevation slopes, and mid-elevation terrain features that allow for drifting snow to accumulate. The new soft slabs will be most pronounced on south through east-facing slopes, but with such high winds can load any aspect because winds swirl and change direction as they pass through the mountains, this is known as cross-loading.

What to do? Look for evidence of fresh drifts and wind slabs that look wavy, rounded, smooth, and pillow, and avoid them.

Any wind slab avalanche that you trigger has the potential to step down into deeper weak layers in the snowpack, creating a very large and dangerous avalanche.

Special Announcement

Please join Utah Avalanche Center forecaster Craig Gordon as he takes a deep dive and reflects on recent close calls along with what’s going on with our current snowpack structure and what's in the store for the future.

Thursday December 22, 2022 6:00PM -Alpha Coffee -7260 Raquet Club Dr, Cottonwood Heights, UT 84121

Recent Activity

There have been no reported avalanches from backcountry skiers and riders since Sunday. Observers continue to report poor snowpack structure in the lower elevations areas outside of the upper Cottonwood Canyons.

Snow and Weather

There was no new snow overnight. As of 5 AM, a few snowflakes have begun falling out of the sky. Temperatures are in the mid-teens and low 20s F. Winds have begun to pick up overnight, averaging 20 mph with gusts up to 30 mph at mid-elevations, and gusting up to 60 mph at upper elevations.

Today, snowfall will increase across the area throughout the day. Peak snowfall rates will occur late this afternoon, into the early evening hours. We could receive 4-8" of new snow before 6 PM tonight. Westerly winds will continue to climb, averaging 20-30 mph with gusts up to 50 mph at mid-elevations. At upper elevations, winds will average 40-55 mph with gusts up to 90 mph. Tonight gusts could hit speeds over 100 mph at upper elevations. Temperatures will remain in the mid-20s F.

Snowfall will continue through the evening, bringing another 4-8" of new snow by tomorrow morning.

The National Weather Service has issued a Winter Weather Advisory through Thursday at 4:00 AM with 6-13" of snow expected. This will be followed up by another storm on Friday.

Additional Info

Read about decision making during MODERATE hazard HERE.

General Announcements

As the end of the year approaches, please consider a donation to the UAC to support avalanche forecasting.

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This information does not apply to developed ski areas or highways where avalanche control is normally done. This forecast is from the U.S.D.A. Forest Service, which is solely responsible for its content. This forecast describes general avalanche conditions and local variations always occur.

Observations and Avalanches

Backcountry Emergency Procedures