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

Wednesday, February 26, 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 Wednesday, February 26, 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 Ski Lifts.

Current Conditions:

Under cloudy skies, winds are very light this morning, less than 10 mph, even across the highest ridges. Temperatures are in the teens. In the last 24 hours, most areas have picked up an additional 1-3” of light density snow. The mostly cloudy skies and cold temperatures of the past few days have preserved the powder on all aspects.

Avalanche Conditions:

Yesterday, southerly facing slopes got in on the avalanche action after lying quietly in wait for most of the winter. A party skinning up one of the south facing Emma ridges above the Town of Alta started getting collapses. The fourth collapse remotely triggered a slide in the steeper gully to their side. The slide was 1 ½ to 2’ deep, 120’ wide, and ran over 600 vertical. It broke in weak facets between two ice crusts. In addition, there were several other reports of collapsing on southerly facing slopes yesterday, and from Sunday and Monday, in the Snake Creek drainage and several drainages in Big Cottonwood. On steep southeast, south, southwest and west facing slopes there are two problems. First, slides can break in the weak facets between or below the crusts. Second, in some areas, there is still remarkably poor bonding of the newer snow to the uppermost ice crust, and new snow slides could be triggered on the steeper slopes.

There has been no change to the stability problems on the shady, northerly facing slopes. Yesterday, a couple staff members looked at the very large slide in No-Name Bowl on Park City side. This slide involved many of the numerous weak layers we have on the shady slopes, including recrystalized graupel, several different layers of buried facets, and a thin ice crust. Yesterday, the new snow was sluffing on steep slopes of all aspects, and some sluffs were fairly large in size. New snow slides and sluffs could trigger some of the deeper weak layers.

With our variable snow pack and numerous weak layers, all steep terrain is avalanche terrain. If you are venturing onto slopes steeper than about 35 degrees, you need to need to access their stability and realize human triggered avalanches are possible.

If the clouds thin today, heating from the sun will rapidly warm the surface snow, possibly triggering some new snow sluffs or shallow slabs. And while the winds are to remain very light, if you are in an area where they pick up, the avalanche danger will increase rapidly.

Activity in the Ogden Area Mountains from the past few days involved half a dozen human triggered slides that were new snow only, up to a foot deep and 100’ wide. There are also reports of sensitive weak layers beneath some of the older hard wind slabs.

The Provo Area Mountains, in the southern part of the range, received more snow and had widespread new snow avalanche activity yesterday on northeast, east, southeast and southerly facing slopes. Most of these slides were started by human triggered sluffs that then triggered slabs, though a couple were remotely triggered from a distance. They were all new snow, averaged 60 to 200’ wide, and some were very long running as is typical of the steep Provo mountain terrain.

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

The avalanche danger is MODERATE on slopes of all aspects, north, east, south and west, which are steeper than about 35 degrees, and above about 9,000 feet. Moderate means human triggered avalanches possible. Sluffs and soft slabs triggered within the new snow have the potential to pull out layers of old snow, especially on slopes facing northwest, north, northeast and east, creating larger dangerous avalanches. Slopes less steep than about 35 degrees have a generally LOW danger.

Bottom Line (Provo Area Mountains):

The avalanche danger today is CONSIDERABLE on and below all slopes approaching 35 degrees in steepness. Human triggered slides are probable and natural slides possible. The danger may rise with direct sun or daytime heating. .

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

Mountain Weather:

Moist, unsettled weather will continue over the area through the weekend. Mostly cloudy skies today, with light snow showers adding up to another inch or two. Highs today in the mid teens at 10,000’ and the mid 20’s at 8,000’. Winds will remain light, less than 10 mph, from the northwest. Partly cloudy skies tonight, with light northwest winds and lows near 10. A chance for light snow tomorrow and again on Saturday.

General Information:

Wasatch Powderbird Guides will probably not be flying today due to weather, but if they do it will be in the Silver, Days, Cardiff and White Pine drainages, with a home run in Grizzly.

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

I will update this advisory by 7:30 on Thursday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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