Avalanche forecast

Salt Lake

Issued Dec 16, 2024valid to Dec 17, 2024Utah Avalanche Center

Avalanche danger

Alpine
Treeline
Below treeline

Out of date — this forecast expired 2 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

Today, there is a CONSIDERABLE avalanche danger on upper elevation northwest-north-east facing aspects for triggering a wind-drifted snow avalanche failing on buried facets. These avalanches could be 2'-3' deep and up to 100' wide running up to 400' vertical. There is a MODERATE avalanche danger on upper elevation west and southeast aspects and mid elevation northwest-north-east facing terrain. The avalanche danger is LOW on all other aspects. Recently formed wind slabs may be supportive enough to allow you to get further onto the slope before they break, making them all the more dangerous. Cautious route finding and conservative decision making is essential.

Avalanche problems

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Likely
Size
2
We now have two buried weak layers in our immature snowpack. One is a layer of facets located 1"-8" off the ground and the other is a buried surface weakness that formed during the early December high pressure and is just under the newest snow. The one near the ground is easy to see in snowpits and is the classic weak snow with strong snow over the top. The harder to find surface weakness is now buried 6"-12" under the most recent new snow and wind. This weak snow will be spotty as it may have been destroyed by high winds and warm temperatures before it was buried by the most recent storm snow. Many of our backcountry observations have included reports of collapsing, cracking, and whumpfing. These are all signs that the snowpack is adjusting and if you see/hear these signs, or see recent avalanche activity then back off and find a lower angle slope to travel on.

Photo (T) with the red arrow pointing to the thin gray line of buried surface hoar (surface weakness) from upper Little Cottonwood Canyon.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
2
Strong southerly winds over the last few days have loaded slopes in mid and upper elevation terrain. The nature of the strong winds is that they can load slopes in odd patterns and may not always distribute snow equally across a slope. Look for areas of wind loading such as thick, pillowy drifts of snow and avoid those slopes. Some of the winds have loaded snow in gully features that may have thin weak snow underneath. These are the zones where you are more likely to trigger an avalanche.

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Recent Activity

Yesterday, we had 6 backcountry avalanches reported to the Utah Avalanche Center. Most of these avalanches failed on north-east facing aspects above 10,000' in elevation. There was one outlier on a southwest aspect in upper Little Cottonwood Canyon at 9,400' that was intentionally skier triggered and may be more representative of northerly facing terrain because of it's location and shading. I imagine that most of the avalanches we saw yesterday had some combination of wind loaded snow over one of our now buried Persistent Weak Layers (PWL). Ski area operations reported a number of intentionally triggered avalanches. As they continue to prepare their terrain for openings, please be respectful of their boundaries. Get the most up to date uphill travel information HERE.

This rider triggered avalanche in the Cardiff Chutes was on an east- northeast aspect at 9,800' elevation.

Snow and Weather

This morning, under partly cloudy skies temperatures are in the mid-teens to mid 20's °F. Winds are blowing lightly at the lower elevations and blowing from the west in the mid-teens gusting to the 20's MPH at the higher elevation weather stations. There was no new snow reported overnight. Yesterday, the winds blew in the strong range and the storm tapered off in the late morning hours leaving behind 3"-8" of snow and .25"-.86" of water with Upper Big Cottonwood Canyon recording the most snowfall. For today, look for partly cloudy skies with temperatures 33-38 °F and winds blowing from the west-southwest 10 gusting to 15MPH at the 9,000' ridgelines and 30 gusting to 45 MPH at the 11,000' ridgelines. There is a trace- 1" of new snow forecast to start later in the afternoon. For the most up to date weather station information check out the UAC's new weather tab HERE.

Snow depths now range from 20"-36" throughout the forecast region.

General Announcements

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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