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Forecast for the Salt Lake Area Mountains

Drew Hardesty
Issued by Drew Hardesty on
Sunday morning, December 3, 2023
AVALANCHES ARE OCCURRING NOW.
The avalanche danger is HIGH on many slopes of the mid and upper elevations. The danger is CONSIDERABLE on many slopes down low.
Avalanches can be triggered at a distance and trigger other avalanches in adjacent terrain.
The TRAVEL ADVICE is easy today: Travel in avalanche terrain is not recommended. This includes below avalanche terrain. Remember that traumatic injury is likely with any avalanche involvement this early season.
Low
Moderate
Considerable
High
Extreme
Learn how to read the forecast here
Special Announcements
Please be aware of uphill travel policies at the ski areas and respect their closures to keep you and their workers safe.
The 5th Annual Avalanche Awareness Week is December 3-10. The week's goal is to save lives through activities that promote avalanche awareness, education, and safety. We have a variety of events around the state. Find an event near you.
Weather and Snow
The Winter Storm Warning continues through Monday morning.
Could a decaying atmospheric river be denied?
It's been a powerhouse: strong wind, heavy dense snowfall, blowing and drifting snow, rising temperatures. And the storm rages on. I'll admit it's a bit of a cruel joke: imagine all this sierra cement over Friday's 5% blower powder...but it's short term pain for long term gain as we build up our snowpack for the winter.
Overnight snow and water numbers are below with storm snow and water. So far...
LCC: 12"/1.18" SWE..... Storm: 36"/2.43" SWE
BCC: 6"/0.59" SWE..... Storm: 18"/1.40" SWE
PC: 6-10"/1.23" SWE..... Storm: 12-20"/up to 1.70" SWE
Ogden: 8-12"/1.40"SWE..... Storm: 14-20"/2.5-4.0" SWE (4.0" at Ben Lomond)
Provo: 6-12"/2.21" SWE (Sundance)..... Storm: 20-30"/3.29" SWE at Sundance
Aside from all the snow, winds from the west-northwest have been merciless and punishing at all elevations. At 11,000', another violent gust just after midnight hit 109mph and even the low/mid elevation anemometers are spinning 25mph gusting 45mph. Mountain temperatures have climbed into the mid to upper 20s.
For today, we'll see continued, albeit diminished, snowfall rates with moderate to strong winds from the west-northwest. Temperatures will be in the mid to upper 20s. I expect an additional 8-14" of snow through tomorrow morning, where the winds, finally, start to lose steam. We start to clear by Monday afternoon with a warming trend pushing mountain temperatures into the upper 30s to upper 40s (mid-elevations) by Tuesday. A weak system follows for Thursday.
Recent Avalanches
Backcountry travelers reported triggering shallow soft slab avalanches in the the wind zone yesterday while others reported very little cohesive slab development. As a sure sign of things to come, one long time observer triggered a large avalanche along the Park City ridgeline from 150' away. The avalanche in West Monitor is estimated to be 2-3' deep and 300' wide, running on the old weak sugary snow from October/November. Ski areas in the upper Cottonwood also triggered large avalanches in this weak layering in upper elevation northerly terrain. Cracking and collapsing are the rule and not the exception.
For a full list, click HERE or find it in the menu above.
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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
You will be able to trigger large avalanches at a distance today that fracture down into the old weak snow from October/November. This weak basal stack of cards exists primarily on westerly to northerly to easterly aspects at the mid and upper elevations (see Brackelsberg photo below. It's very easy to see the strong over weak poor structure.) Forecaster Greg Gagne's excellent observation from yesterday provides more details HERE.
These avalanches may be 2-4' deep and hundreds of feet wide. They are not to be messed with. Cracking and collapsing state the obvious, as it were, but the only prudent terrain choices are on low angle terrain today.
Avalanche Problem #2
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
One of my colleagues - Dave Kelly - who lives at Alta remarked this morning that "It's a bit Alaskan out here". You'll find an endless supply of soft slabs of wind drifted snow in a variety of encatchment areas, both along the ridgelines and well below. These large smooth pillows may be up to 4' deep or more in exposed terrain and will also be sensitive to the weight of a backcountry traveler. Be aware that the cornices are growing and becoming unstable - any cornice fall is likely to trigger an avalanche below.
Avalanche Problem #3
New Snow
Type
Location
Likelihood
Size
Description
Heavy dense snowfall is coming in on a warming trend and is "upside-down"; that is - higher density snow falling on lower density snow - and it's a recipe for trouble. Similarly, rain on snow at the lowest elevations will lead to unstable wet snow conditions. Shooting cracks are a clear sign of instability (Brackelsberg photo)
Additional Information
Forecaster's Corner:
Matsuo Bashō lived in Japan from 1644-1694 and is often viewed as the the avalanche hunter's favorite poet. His most famous haiku, below.
❄️
Come, let's go
Snow-viewing
Til we're buried.
General Announcements
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.
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