Wasatch Cache National Forest

In partnership with: The Friends of the Utah Avalanche Forecast Center, Utah Department of Public Safety Division of Comprehensive Emergency Management, Salt Lake County, and Utah State Parks


The Utah Avalanche Center Home page is: http://www.avalanche.org/~uac/



Avalanche advisory


Tuesday, February 18, 2003

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Good Morning.  This is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Tuesday, February 18, 2003, and it’s 7:30 in the morning.  We would like to acknowledge one of our partners, the Friends of the Utah Avalanche Center, generously supported by Alta Lifts.


Current Conditions:


Temperatures are cold again this morning with ridge top temperatures around 10 degrees with a 20 mph wind from the west, gusting to 30 on the exposed peaks.  Two days ago we had a violent little graupel storm.  Graupel is that kind of Styrofoam ball snow and 6-8 inches fell in the Cottonwood Canyons with half that amount elsewhere.  Yesterday, the south facing slopes got sun crusted but there’s still nice, soft dry snow on the slopes facing the north half of the compass.


Avalanche Conditions:

We heard about a couple backcountry avalanches from yesterday.  First, some snow boarders went out of bounds from Brighton and the third boarder down the west side of Millicent Peak triggered a soft slab avalanche about 100 feet wide and 1- 2 1/2 feet deep on a 38 degree slope, which ran about 300 vertical feet.  Luckily, the boarder had his speed built up and was able to outrun the slide.  It broke below the rain crust from February 13th and the boarder triggered it from the deepest part of the fracture, probably in a pool of graupel that rolled off the cliffs.  The second avalanche occurred in the backcountry on the east side of Clayton Peak near Brighton, which was triggered remotely by explosive avalanche control at Brighton.  It broke 3-4 feet deep, 100 feet wide and broke into deeper layers of faceted snow. 


Today, we’re worried about two different avalanche problems:

First, you may be able to trigger some localized avalanches within the new snow.  For instance, the graupel snow which fell on Sunday tends to roll off of cliffs and steep slopes and pool on the flatter aprons underneath steep slopes.  So you should continue to watch out for places like because they have an unusually heavy load of new snow.  Also, wind from Sunday and also last night created localized deposits of wind drifted snow.  As always, you should avoid steep slopes with recent wind drifts.

Second, is our old problem, the weak layers of faceted snow and depth hoar near the ground, which formed during clear weather in December and January.  We have had a coupe inches of water weight added over the past week and this is enough to stress some of these deeper weak layers enough to make them sensitive to human triggers.  We’ve had three different avalanches break into these deeper weak layers in the past three days including the fatal Gobbler’s Knob avalanche on Saturday, Wolverine Cirque on Sunday and the east side of Clayton Peak yesterday.  Especially watch out for steep, slopes with a thin snowpack above about 9,000’ in elevation. 


Both of these avalanche problems are quite localized, meaning that you could trigger an avalanche only on a small percentage of the terrain, but especially with the deeper avalanches, the consequences can be quite severe, as we discovered with the Gobbler’s Knob avalanche on Saturday.


Bottom Line (SLC, Park City, Ogden and Provo Area Mountains):

There is also a MODERATE (or localized) danger of triggering an avalanche within the new snow from recent wind drifting or graupel pooling beneath cliffs.  There is also a MODERATE danger of triggering an avalanche on deeper weak layers of old, faceted snow on slopes that face the north half of the compass, plus east facing slopes, steeper than about 35 degrees and above about 9,000 feet, especially in thin, rocky areas. 


Western Uintas – call 1-800-648-7433 or click here for weekend and holiday forecasts.


Mountain Weather:

Today we have a weak system of unstable air coming into Utah this afternoon and tonight, which could give us some scattered, light snow showers and probably not add up to more than 2-4 inches.  Ridge top temperatures will warm up to around 15 degrees today with a west wind around 15 mph and blow around 25 mph tonight, switching from southwest to northwest.  We should have a bit of a break on Wednesday and then another, probably stronger system on Thursday.


General Information:

Wasatch Powderbird Guides will be flying in Days, Silver and Cardiff today with a home run in Grizzly Gulch.


To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, remember that the information you have could save someone’s life.  Please leave a message on our answer machine at (801) 524-5304 or 1-800-662-4140, or email to [email protected] or fax to 801-524-6301.  The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content.  This advisory describes general avalanche conditions and local variations always occur.


Evelyn Lees will update this advisory by 7:30 on Wednesday morning.


Thanks for calling!




National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings: