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

Thursday, December 12, 2002

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Good Morning. This is Ethan Greene with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Thursday, December 12, 2002, and it’s 7:30 in the morning.

The Utah Department of Transportation will be testing their artillery in the Storm Mountain/Stairs Gulch Area on Friday December 13 around noon. Backcountry travelers should avoid the Storm Mountain Area Tomorrow.

Current Conditions:

Overnight the mountains picked up an additional 1 to 2 inches of snow. This moist storm also produced a rime crust in some locations. Storm totals since Tuesday evening are 2 to 4 inches of snow with 0.1 to 0.4 inches of water. Yesterday afternoon westerly winds increased into the 25 mph range with some gusts over 50 mph along the highest ridgelines. This morning average wind speeds in upper elevation areas are in the 20 mph range with some gusts over 30 mph.

Avalanche Conditions:

With only 2 to 4 inches of new snow in the backcountry the avalanche danger has not increased very much. Westerly winds have created some sensitive wind drifts especially in upper elevation areas. These fresh wind deposits will be 6 to 12 inches deep and they are sitting on a variety of hard crusts and weak surface snow. If you’re poking around on an upper elevation ridgeline you should look out for sensitive wind drifts especially on slopes that are steeper than about 35 degrees.

Keep in mind that this new snow may effectively hide and protect the near surface facets and surface hoar deposits, potentially setting us up for a nasty round of avalanches when a larger storm arrives.

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

The avalanche danger remains generally LOW in the Wasatch Mountains. However, there is a MODERATE danger of triggering a fresh wind drift on slopes steeper then about 35 degrees.

Mountain Weather:

The low-pressure trough that brought us snow yesterday is moving off to the east and a high-pressure ridge is building over the southwestern U.S. Moist northwest flow associated with the trough will bring overcast skies and scattered snow showers to the Wasatch Mountains this morning. As high pressure builds in this afternoon, skies will become mostly cloudy. Temperatures will rise into the mid 30’s at 8,000’ and mid 20’s at 10,000’. The moderate west and northwest winds we saw overnight should taper off during the day. Friday and Saturday skies should be partly to mostly cloudy with mild temperatures. Another low pressure system is forecast to bring snow to the Wasatch on Sunday.

General Information:

Bruce Tremper will be giving a free avalanche awareness talk for the Wasatch Mountain Club tonight at the Zion Lutheran Church (1070 Foothill Drive). The talk is free, open to the public, and starts at 7:00 pm.

To report backcountry snow and avalanche conditions, especially if you observe or trigger an avalanche, call (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 Friday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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