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

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Avalanche advisory

Tuesday, NOVEMBER 25, 2003 7:30 am

Good morning, this is Andrew McLean with the Forest Service Utah Avalanche Center with your avalanche and mountain weather advisory. Today is Tuesday, November 25, 2003, and it’s 7:30 a.m.

Current Conditions:

The soft, stable powder of two days ago was attacked by 20 mph winds with gusts up to 40 and warming temperatures yesterday. With an overnight low of seven degrees and a high of 30 at mid elevations, the snow has consolidated into various forms of wind slabs, pockets of powder, sustrugi and ankle grabbing ridges in the exposed areas. Although there was only a trace of new snow last night, the old snow has blown enough to cover up tracks and make for character building turning conditions. Today, the 8,000’ temperatures are expected to be in the mid teens with a moderate wind out of the west, shifting to the northwest this evening.

Once again, the best turning conditions will be found in sheltered, mid elevation areas that have escaped the wind.

Avalanche Conditions:

This combination of blowing snow and warming temperatures have created large, fragile cornices that are sensitive to human triggers and are breaking off further back than expected. These breaking cornices are producing large, dangerous chunks that would be nasty to be caught under and can trigger soft slab avalanches in the wind loaded pillows beneath them. In the Ogden Mountains yesterday, a cornice drop produced a 1’ deep by 30’ wide soft slab avalanche that ran 300’ on a southeast slope. This slid on a 32 degree angle on a weak layer of graupel. The wind was predominately from the west, but shifted throughout the day, loading a variety of high elevation aspects. Stability tests have been producing easy shears on buried graupel in these wind deposited areas, with only a few, small slab avalanches being reported. As a general rule of thumb, avoid any large pillow-like pods of wind drifted snow lurking just off of ridgelines or below cornices.

Bottom Line (Salt Lake, Park City, Ogden and Provo area mountains):

Mid elevation, sheltered areas have the best conditions and a LOW avalanche hazard today. Higher elevations have a MODERATE hazard on steep slopes with recent deposits of wind loaded snow.

Mountain Weather:

Expect a transitional day of light snow, moderate winds and overcast skies today as a storm starts to build this evening. The winds will shift from the west to the northwest, as a cold air mass works its way down into the Northern Wasatch Mountains. 1-3” of new are possible by this afternoon, with the bulk of the storm arriving tonight and delivering up to a foot of snow in the Cottonwood Canyons by Wednesday evening and possible snow down in the Salt Lake Valley. This northwest flow, aided by some orographic lift and potential Lake Effect enhancements should deliver some great snow just in time for Thanksgiving turning and riding. The winds will build from moderate to strong along the ridgetops and continue throughout the storm. After a lull on Thursday, another storm is expected to roll in over the weekend.

3-Day Table	3-Day Graph	7-Day Table
Ogden Mountains	Ogden Mountains	Ogden Mountains
SLC Mountains	SLC Mountains	SLC Mountains
Provo Mountains	Provo Mountains	Provo Mountains

For specific digital forecasts for selected mountain areas from the National Weather Service, click the links below or choose your own specific location at the National Weather Service Digital Forecast Page:

General Information:

If you are getting into the backcountry, please give us a call and let us know what you’re seeing, especially if you trigger an avalanche. You can leave a message at 524-5304 or 1-800-662-4140. Or you can e-mail an observation to uac@avalanche .org, or you can fax an observation 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.

This advisory will be updated Wednesday morning.

Thanks for calling.

_____________________________________________________________________________

For more detailed weather information go to our Mountain Weather Advisory

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

http://www.avalanche.org/usdanger.htm