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

Saturday, January 4, 2003

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Good Morning. This is Evelyn Lees with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory. Today is Saturday, January 4, 2003, and it’s 7:30 in the morning.

Current Conditions:

It was down right tropical last night, with lows in the upper twenties to low thirties. Across the highest peaks, the winds are out of the west averaging 20 to 30 mph. Once off the higher ridgelines, the winds are less than 10 mph. Dense, dry powder remains only on the shady mid and upper elevation slopes. Slopes receiving any significant sun and all slopes below about 8,500’ will have shin bashing crusts early this morning, and once the day heats up will turn to the consistency of those Thanksgiving mashed potatoes. So throw some skin wax into your pack.

Avalanche Conditions:

There were 3 more human triggered avalanches in the backcountry yesterday. A group along the Park City ridge line remotely triggered a 2 foot deep, 150’ wide slide in South Monitor. It was adjacent to the slide that Bruce triggered Wednesday, leaving everyone wondering why on earth it didn’t also slide on Wednesday. Also remotely triggered was a smaller, 50’ wide, 2’ deep slide in the Bear Trap gully. And finally, a snowmobiler triggered 100’ wide slide to the ground in the Snake Creek drainage on a slope that had been previously tracked. Resort control work in Little Cottonwood released numerous hard slabs, 100 to 300’ wide, a few with bizarre patterns incidents that seem to happen when surface hoar or facets are the weak layer.

This scary pattern is not changing - most of these slides are failing on a faceted weak layer near the ground, above 9,500’, on slopes steeper than about 35 degrees and most commonly on north, northeast and easterly facing slopes – but there are exceptions to each of these. All this avalanche activity means that the facets have not adjusted to the load of snow they are supporting, and on many slopes all it’s going to take today is a 150 lbs or a hard turn to tip the balance. The only way to be sure of not getting on the wrong side of a ton of snow rocketing down a slope at 60 mph is to travel on low angle slopes, about 30 degrees or less, that are not connected to steeper slopes.

To further complicate the picture, the unusually warm temperatures and direct sun will also add to the instability today, heating up the snow surface. Wet loose sluffs could pull out deeper slabs. Even the shady slopes may heat up if we get some high, thin clouds this afternoon. So when the roller balls start pin wheeling down the slope or the snow gets mushy, it’s time to get off of and out from under steep slopes.

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

The avalanche danger remains CONSIDERABLE on slopes facing northwest, north, northeast and east, above about 8,500’ and about 35 degrees or steeper; that’s about the steepness of a black diamond slope at a ski resort. Human triggered avalanches are probable in these areas. There is a MODERATE avalanche danger on southerly facing slopes, possibly rising to CONSIDERABLE with daytime warming. The danger is LOW danger on slopes less than 30 degrees steepness, although slides can be triggered from nearby low angled terrain.

Western Uintas – call 1-800-648-7433

Mountain Weather:

A weak Pacific storm system will approach the area this evening, bringing a chance for light snow tonight into Sunday morning. Ahead of the disturbance, this morning’s clear, sunny skies will give way to increasing high clouds this afternoon. Highs today will be in the low 40’s at 8,000’ and the low 30’s at 10,000. The light westerly ridge top winds will increase this afternoon, into the 15 to 25 mph range. Light snow should start after midnight, with accumulations of a few inches possible by Sunday afternoon. A strong ridge will build into the area for the first half of next week.

General Information:

For more details on recent avalanche activity call 364-1591.

Wasatch Powderbird Guides will fly today in upper Silver Fork, mid elevation Cardiff, and White Pine.

The Friends of the Utah Avalanche Center will offer an intensive 3-day avalanche class January 18-20. You can sign up at the Black Diamond Retail Store or call them at 801-278-0233.

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.

Ethan Greene will update this advisory by 7:30 on Sunday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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