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Forecast for the Salt Lake Area Mountains

Issued by Nikki Champion for Tuesday, January 4, 2022
The avalanche danger is CONSIDERABLE on mid and upper elevation slopes facing west through north and east. Avalanches may break down 4-6' deep (possibly deeper) and hundreds of feet wide. Natural avalanches are possible, and human-triggered avalanches are likely. Avoid this terrain because those avalanches will kill you.
Watch for and avoid any freshly formed wind drifts on slopes facing southwest, south, and southeast which have a MODERATE avalanche danger at mid and upper elevations.
Pay attention to changing weather patterns. As this next storm system develops, it will bring new snowfall, warm temperatures, and high winds, with that the avalanche danger will rapidly rise.
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Learn how to read the forecast here
Weather and Snow
Temperatures this morning are in the upper teens to low 20s F. Overnight, southwesterly winds increased drastically and will continue to increase into the morning. At mid-elevation bands, they are blowing 20-30 mph gusting 45 mph. At the upper elevation ridgelines, they are gusting near 80 mph.
Today temperatures will generally rise to the upper 20s F, but lower elevation locations should have temperatures in the mid-30s F. Clouds will continue increasing into the morning, bringing light snowfall and high winds. Snowfall rates should remain less than one inch an hour today, with peak snowfall rates between the late morning and early afternoon. We can expect 3-6" of new snow by dinner. Winds will continue to increase throughout the morning and transition more westerly. Winds will blow 20-30 mph, with gusts up to 35 mph at mid-elevations. At upper elevations, gusts may reach up to 70 mph.
While we get a bit of snow today, it will taper off this evening and the heavier snowfall arrives Wednesday morning to Thursday morning. This storm looks like it will have strong winds, increasing temperatures, and increasing snow densities.

Warm temps and a few days of intermittent sunshine have warmed the snow on south-facing slopes and most will have a slight crust this morning. Coverage is fantastic, and settled snow depths, even at lower elevations are 3-4 feet. Upper elevation areas and the upper cottonwoods have snow depths up to 6-7 feet.
Recent Avalanches
Yesterday, there were no new avalanches reported in the backcountry, but reports from avalanches triggered this past weekend continue to roll in. Ski resorts and DOT continue to get results with explosives in upper elevation NW-N-E facing terrain.
View all the recent avalanche activity HERE.
Yesterday, we went out and looked at the remotely triggered avalanche on the Firewater Run of Little Water Peak. This avalanche failed deeply on a layer of facets above a crust, and then stepped down to the ground in many places. Below shows the crown depth at one of it's deepest points, close to 12', while the average depth was closer to 4'. Find the full observation here.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
The situation is very simple - there is a persistent weak layer (PWL) of old, faceted snow near the ground with 3-10 feet of snow on top of it. This layer has been fracturing and producing large and destructive avalanches. Winds increased from the south and have likely been loading the slopes where this PWL exists. The likelihood of triggering these massive avalanches has gone down just a little in recent days, but the size and destructive potential of these slides hasn't changed.
This layer exists on west, north, and east-facing slopes where old snow lingered and weakened in November and was buried by December snowfall. It doesn't exist on south-facing slopes because it melted away in November, and December snowfall landed on bare ground on those slopes.
Over the last week, snowfall containing up to 8 inches of water has been added to the snowpack. We focus on water amounts because that tells us how much weight is added to the snowpack. For a slope the size of a football field, snow with 8 inches of water weighs 2,800,000 pounds. Imagine that amount of snow crashing downhill.
Video from the Firewater Avalanche off of Little Water Peak in Big Cottonwood Canyon.

How will we know when this avalanche problem heals? That's a tough question to answer, and we mainly have to let the snowpack answer it. For now, avalanches are still happening and that's all I need to know. As we look into the future, it will heal, but I can't tell you when. We will be monitoring the snowpack and avalanche activity and keep you updated.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Since yesterday, the southwest winds have increased drastically and have likely been transporting 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 avalanche problem listed above.
While these south winds have mostly formed drifts on northerly facing slopes, they can load any aspect at mid and upper elevations because winds swirl and change direction as they pass through the mountains, this is known as cross-loading.
What to do? Avoid any steep west, north, or east-facing terrain that has the avalanche problem listed above. If riding south-facing avalanche terrain, look for evidence of fresh drifts and wind slabs that look wavy, rounded, smooth, and pillowy and avoid them as well. Fortunately, those fresh drifts are easy to see and go around.
General Announcements
Who's up for some free avalanche training? Get a refresher, become better prepared for an upcoming avalanche class, or just boost your skills. Go to https://learn.kbyg.org/ and scroll down to Step 2 for a series of interactive online avalanche courses produced by the UAC.
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.