Forecast for the Ogden Area Mountains

Trent Meisenheimer
Issued by Trent Meisenheimer for
Wednesday, February 7, 2024
UPDATE 1:36 PM: Avalanches are happening now. Strong winds and heavy snowfall have overloaded the mountains. The avalanche danger has reached HIGH danger and traveling in avalanche terrain is NOT recommended.
The avalanche danger is CONSIDERABLE across the mid and upper elevations for several avalanche problems. Pick your poison: Hard and soft slabs of wind-drifted snow. Soft slabs of new snow. Or you could trigger an avalanche that fails on a buried persistent weak layer. It's complicated and very dangerous.
In any case, the avalanche you trigger is likely a few hundred feet wide and could be 2 to 4 feet deep.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
Another 3.0-6.0 inches of new snow fell overnight, containing 0.25-0.80 inches of water. This morning, it's snowing in places, and the southerly winds continue their onslaught, blowing 10-20 mph with gusts into the 20s and 30s. Mountain temperatures range from 25-34 °F.
Today, we should see continued snowfall throughout the morning on a southerly flow with winds blowing 10-20 mph. By this afternoon, the wind will finally change direction, blowing from the west and then the northwest. Once the wind changes, the snowfall is expected to be heavy at times. Throughout the day today, we could see an additional 7-17 inches of new snow (0.45-1.2 inches of water)
Recent Avalanches
Yesterday's avalanche that caught my eye was a remotely triggered avalanche from a piece of terrain in upper Little Cottonwood on Sugarloaf Peak that represents a backcountry snowpack. Two patrollers were heading out to run routes and got the slope to collapse. The avalanche was 2 feet deep and 300 feet wide, failing on faceted snow (picture below).
In the Ogden area, control work has released avalanches that failed within the new storm snow, running on a melt-freeze crusts from the very warm temperatures last week. These avalanches were roughly 1-2 feet deep and 300 feet wide.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
It's been 60 straight hours of south winds blowing 10-25 mph with gusts into the 20s and 30s. These are the perfect speeds for drifting snow onto lee slopes. These winds, combined with feet of dense, heavy snow, have created both soft and hard slabs of wind-drifted snow in the starting zones. These will not be small avalanches.
If you trigger a wind-drifted snow avalanche, it's possible it can step down into deeper weaker layers, creating a much larger avalanche.
Travel Advice: Very dangerous avalanche conditions. Traveling in avalanche terrain is NOT recommended. This means being on or under any steep wind-drifted slopes.
Avalanche Problem #2
New Snow
Type
Location
Likelihood
Size
Description
I suspect the warm dense snow is well bonded and avoiding wind-loaded slopes will be the key to avoiding avalanches. However, it's worth assessing the new snow. With up to 2.20 inches of water in the new snow, it could make a meaty soft slab avalanche. Check small, steep, test slopes; step or ride above the track from another person; and do a few snowpack tests to see how the new snow has bonded to itself and underlying layers. Look for a melt-freeze crust, maybe 2-3 feet deep, that formed during recent warm, sunny weather and assess how the snow is bonding to that crust. Control work is producing avalanches on that crust in the Ogden area.
Avalanche Problem #3
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
It's complicated. But it's also so simple.
The complicated part: is where and when do you trigger an avalanche on our persistent weak layer? Our weak layer is now buried roughly 2-6' deep with a thick, hard slab of snow above. It seems the most likely spot to trigger an avalanche will be in a steep thin rocky area.
One slope is stable and then another can produce a large, deep and dangerous slab avalanche. How do you know or manage which option you get? I honestly do not know how to manage this problem or provide any advice in dealing with this problem with how variable the snowpack is.
Here comes the simple part. I would avoid avalanche terrain for now and let the snowpack adjust and settle more. This added weight is a good thing for the snowpack long-term. However, today the added weight is only adding stress and increasing the likelihood of triggering an un-survivable avalanche.
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.