Forecast for the Uintas Area Mountains

Mark Staples
Issued by Mark Staples for
Friday, December 31, 2021
AVALANCHE CONDITIONS ARE VERY DANGEROUS
The avalanche danger is HIGH near and above treeline. The avalanche danger below treeline is CONSIDERABLE. Avalanches breaking in old snow near the ground will be catastrophic and unsurvivable.
Avoid being on or near any slope steeper than 30 degrees. Flat terrain underneath steep slopes is a dangerous place to be because avalanches can run long distances.

What to do and where to go? The Uintas are blessed with many open meadows and rolling terrain that isn't steep enough to produce avalanches. Go to this gentle terrain today, but make sure to stay far away from any steep slopes.
Low
Moderate
Considerable
High
Extreme
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Avalanche Warning
What
THE AVALANCHE DANGER IS HIGH FOR THE WARNING AREA AND TRAVEL IN AVALANCHE TERRAIN IS NOT RECOMMENDED.
When
IN EFFECT FROM 6 AM MST THIS MORNING TO 6 AM MST SATURDAY
Where
FOR THE MOUNTAINS OF MUCH OF THE STATE OF UTAH, INCLUDING THE WASATCH RANGE...BEAR RIVER RANGE...UINTA MOUNTAINS...AND THE MANTI-SKYLINE...THE FISH LAKE REGION…PAHVANTS…TUSHARS…AND THE CEDAR CITY AREA MOUNTAINS.
Impacts
HEAVY SNOWFALL AND STRONG WINDS HAVE CREATED VERY DANGEROUS AVALANCHE CONDITIONS. BEING CAUGHT IN ANY AVALANCHE IS LIKELY TO BE UNSURVIVABLE. STAY OFF OF AND OUT FROM UNDER SLOPES STEEPER THAN 30 DEGREES.
Weather and Snow
NOWCAST-
Since yesterday 10-16 inches of snow has fallen in the Uinta Mountains, and IT'S STILL SNOWING this morning. Temperatures began dropping yesterday afternoon, and this morning they range from single digits F at upper elevations to the mid-teens F at most other places. Strong winds blew from the south yesterday (average 35-50 mph gusts up to 65 mph), but they eased this morning averaging 20 mph gusting to 30 mph from the west. At lower elevations, they are blowing 5-10 mph.
FORECAST-
Snow should continue for most of the day with an additional 4-6 inches of very low-density snow accumulating. Winds will ease a bit more and blow from the northwest by the end of the day bringing more cold air. Temperatures won't warm and should begin falling this afternoon.
FUTURECAST-
Snowfall ends by tomorrow and temperatures will be near zero degrees F. Skies will be clearing tomorrow afternoon, and the sun will be a very welcome sight with such cold temperatures.

Snowfall numbers over the last week are impressive and a major red flag. Here are the water numbers since December 23 from SNOTEL sites. As a general rule of thumb one inch of water equates to 12 inches of snow.
North Slope to Mirror Lake Hwy-
Chalk Creek - 5.4" H2O
Hayden Fork - 4.3" H2O
Trial Lake - 7.2" H2O
South half of the range-
Currant Creek - 5.7" H2O
Daniels-Strawberry - 5.5" H2O
Looking for real-time temps, snow, or wind?
Click HERE and then on the "western Uinta" tab for western Uinta specific, weather station network.
Recent Avalanches
A few avalanches have been sporadically observed and reported; however, clouds and snowfall have limited visibility during the last week. I don't think we really have a sense of the avalanche activity. What we know is that there have been avalanches, and many have been covered by recent snowfall.
Avalanches today can be hundreds of feet wide and 3-5 feet deep or more in wind-loaded locations.

Click HERE for a list of recent avalanches.
A list of all other observations is found HERE

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Avalanche Problem #1
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
A persistent weak layer of faceted snow near the ground will produce hard and soft slab avalanches today. Dense snowfall and strong winds in December created a very stiff slab on top of this weak layer. The good news is that it is very supportable. The bad news is that:
  • Avalanches will break hundreds of feet wide.
  • It may not be the first person on a slope that triggers one of these avalanches, it may be the second, third, fourth, etc. who triggers it.
  • Seeing tracks on a slope DOES NOT mean it's safe.
  • Avalanches may be triggered from flat terrain underneath steep terrain.
  • Being underneath a steep slope, even if you're not on it, is not a safe place to be.
This weak layer exists on any slope that harbored old snow in November. Most low elevations slopes and south-facing slopes don't have this layer. However, it's easy to lose track of which way is north and south, especially on a snowy day like today, so I'd just assume it exists everywhere for the moment and avoid all avalanche terrain.
Slopes loaded by south winds are the exact ones where this weak layer exists. The addition of wind-drifted snow will make avalanches even larger, deeper, and more deadly.
See the slab of snow breaking on this weak layer in my video below.
Avalanche Problem #2
New Snow
Type
Location
Likelihood
Size
Description
There is simply A LOT of new snow, and that is a red flag by itself. Most of the new snow is "right side up" which means it's denser underneath and lighter on top. For this reason, I mostly expect sluffing and dry loose avalanches in the new snow. However, I've been surprised by big storms in the past, and the slightest change in density, change in snowflake shape during the storm, or the slightest breath of wind during the storm can allow the new snow to produce soft slab avalanches.
These new snow avalanches may be a foot or two deep and will surprise you with how much debris they can produce. Looking ahead, the new snow will bond to itself in the next 24 hours.
Additional Information
Curious about what our forecast staff has been thinking about the snowpack, avalanches, and the current situation? Listen to this special evening meeting we had last night on zoom.
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General Announcements
The information in this forecast expires 24 hours after the day and time posted, but will be updated by 07:00 Friday December 31st.
Before it gets too crazy, now is the time to book an avalanche awareness presentation for your group, club, or posse. You can reach me directly at 801-231-2170 or [email protected]
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.