UDOT PLANNED AVALANCHE CLOSURES!!

Forecast for the Provo Area Mountains

Mark Staples
Issued by Mark Staples on
Saturday morning, December 22, 2018
New snow and increased winds overnight have created heightened avalanche conditions on any slope with wind drifted snow. You can trigger slabs of wind drifted snow on these slopes making the avalanche danger MODERATE at mid and upper elevations. In isolated locations with wind drifted snow, there remains a chance of triggering an avalanche at the ground. To find good riding conditions and good stability, ride slopes not affected by the wind.
Low
Moderate
Considerable
High
Extreme
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Weather and Snow
Snow fell yesterday morning and late last night totaling 2-4 inches (0.2-0.4 inches of water).
Temperatures dropped overnight and are in the high teens and low 20s F this morning.
Winds increased overnight and this morning are blowing westerly 20-25 mph gusting 35 mph.
Today a short lived ridge of high pressure will move over the area. Skies will slowly clear and winds should ease with temperatures climbing into the upper 20's F. More snow should come with another storm system on Monday.
There should be a noticeable ice crust under the new snow on south facing slopes and low elevation slopes where the snow was a bit damp yesterday and now refrozen this morning.
Recent Avalanches
Yesterday afternoon some shallow and small soft slabs of new snow and wind drifted snow produced avalanches at ski areas in the Cottonwood Canyons. I expect similar activity occurred at upper elevations in the Provo area mountains.
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Avalanche Problem #1
Wind Drifted Snow
Type
Location
Likelihood
Size
Description
Westerly winds increased overnight and should have formed slabs of wind-drifted snow this morning. Look for and avoid these fresh wind slabs under ridge lines and along cross loaded ridges.
Another reason to avoid these wind loaded areas is that they may have added just enough weight and stress to the snowpack to cause an avalanche to break on weak faceted snow near the ground. See avalanche problem #2 below.
Avalanche Problem #2
Persistent Weak Layer
Type
Location
Likelihood
Size
Description
We have a lot of uncertainty in snowpack conditions at upper elevations in the Provo area mountains. What we know is that a thick (2-3 feet) slab of snow rest on a persistent weak layer of faceted snow near the ground. This layer may be mirroring what we've seen in the Salt Lake mountains where it has become somewhat dormant, but we don't have enough data to say for sure. Steep rocky northerly facing terrain at upper elevations with an fresh load of wind drifted snow is the most likely place for an avalanche to break at the ground. Other terrain has this persistent weak layer, but it is a much thinner layer and less of an issue.
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.