Avalanche forecast

Ogden

Issued Dec 22, 2020valid to Dec 23, 2020Utah Avalanche Center

Avalanche danger

Alpine
Treeline
Below treeline

Out of date — this forecast expired 6 years ago. You’re viewing past conditions, not the current bulletin.

Highlights

A CONSIDERABLE avalanche danger exists on many slopes at the mid and upper elevations. Human triggered avalanches 1-2' deep remain likely...and may still be triggered from a distance.

The danger for new snow and wind slabs will also be on the rise today. Know that any new snow avalanche in steep shady terrain may step down and trigger a much deeper avalanche.

Conservative decision making and awareness of changing conditions will be essential today.

Avalanche problems

Persistent Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Likely
Size
2
These avalanches are what we call 'Unmanageable' - that is, they are predictable in their unpredictability: they may be triggered at a distance or from below. Here's a good example yesterday from avalanche pro Bill Nalli - While conducting a snow test in safe but representative terrain in the Brighton backcountry, "propagation happened after 14 taps. After spending 15-20 minutes in the snow pit, while putting my skis back on to fill in the hole, the entire slope collapsed up to 30' around where I was standing."

Continue to give yourself plenty of margin. Travel advice would be to stick to low angle terrain until the snowpack has adjusted.

The snowpack has a hard time adjusting with every event that adds additional stress - like this morning's strong southwesterly winds and today/tonight's additional snowfall.
Wind Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
2
Although yesterday's sun and warming may have limited the overall snow available for transport, there is some...and there will likely be more drifting during and after the midday cold front. Look for and avoid any fresh deposits of wind blown snow. Owing to previous and expected moderate to strong winds, drifts may be found on a variety of aspects although they'll be more pronounced along the higher elevations.
Storm Slabs
N
NE
E
SE
S
SW
W
NW
Alpine
Treeline
Below treeline
Likelihood
Possible
Size
2
By the afternoon, you may be able to trigger shallow new snow avalanches in the steepest terrain. The new snow is likely to bond fairly well with many of the warm, corrugated crusts on the east to south to west aspects and bond less favorably on the northerly aspects. Note that new snow avalanches are particularly sensitive when snowfall rates are the highest....and aspect doesn't matter.

Special Announcement

Thanks to the generous support of our local resorts, Ski Utah, and Backcountry, discount lift tickets are now available.

Support the UAC while you ski at the resorts this season. Tickets are available here.

Recent Activity

We did not hear of any avalanche activity in the Ogden area mountains, although one avalanche professional described conditions as "spooky, with large collapses and long running shooting cracks".

On Sunday, we did hear reports of a skier caught and carried in an avalanche in the Bailey Spring area near the Cutler Ridge area of Ben Lomond...not far from a larger natural avalanche nearby 1-2' deep and 350' wide. These were on a steep easterly facing aspects at roughly 8600'.

(thanks to Joe Keeler for the report of the natural)

Snow and Weather

Skin wax on Solstice.

Saturn and Jupiter kiss.

Strange year gets stranger.

The Situation:

Skies are clear...but not for long.

A sharp and quick hitting cold front will arrive before noon and snowfall will continue into the night. The NWS has issued a Winter Weather Advisory and - if everything aligns right - the Ogden area mountains may see 4-7" of low density snow. Southwesterly winds picked up in the early morning hours with hourly averages of 30-35mph. Gusts along the Ogden skyline have reached 60mph. Current mountain temps are in the upper 20s up high, the upper 30s down low. The highest elevations may flirt with the single digits by late tonight. Unfortunately it does look as if the northwest winds will remain gusty well after frontal passage today.

We'll need this snow - wind, sun and terribly warm temperatures have taken their toll on the snow conditions.

The Outlook:

We should see clearing skies tomorrow through Friday. We'll see gradually warming temperatures through the end of the week with a storm slated for Saturday that should bring another round of snow.

Additional Info

Many years ago, one of the Little Cottonwood Canyon snow rangers, Peter Lev, attempted to find a correlation between the moon's gravitational pull with avalanche activity. His "tidal charts" are still used today by some avalanche operations. He recently told me that the original idea came from his co-worker Binx Sandahl. I wonder what their opinions would be of the Jupiter and Saturn overlap in the early evening Solstice sky? (photo of the planets and the moons of Jupiter sent by one of Lev's old colleagues). The last time the planets appeared this close and could be seen from the ground was in 1226.

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

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