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

Monday, December 23, 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 Monday, December 23, 2002, and it’s 7:30 in the morning.

Current Conditions:

Overnight a trace to an inch of new snow fell in the mountains. Temperatures dropped below 10 degrees at both 8,000’ and 10,000’. The winds have been from the east in the 10 mph range. Along the highest ridgelines the wind has been a bit stronger with sustained speeds in the 20 mph range and gusts over 30 mph.

The snow surface remains mostly supportable. You can still break through into weaker snow if you’re not gentle on your skis or snowmobile. Some south facing slopes below 9,500’ have a thin crust just below the surface from a few days ago.

Avalanche Conditions:

Our current string of human triggered avalanches continued yesterday. On a northeast facing slope of the Pink Pine Ridge a group of skiers triggered a hard slab avalanche. The slide was about 1’ deep and 75’ wide. Two snowboarders traveling through the Wilson Fork drainage triggered 3 pockets on slopes steeper than 35 degrees. Each slide was about 1’ deep and 25’ wide. There was a remotely triggered avalanche off the northwest side of Davenport Hill in the Sliverfork drainage. And to top things off a group of skiers triggered an avalanche that was 2’ deep and 600’ wind in the Wolverine Circ/Twin Lake Pass area. All of these avalanches occurred on northeast through west aspects that were steeper than about 35 degrees.

So with no recent natural activity and several human triggered avalanches each day, what is the avalanche danger? According to the U.S. danger scale we have a moderate danger of natural avalanches and a high danger for human triggered avalanches. The important thing to remember is not a one word summary of the avalanche conditions, but what is actually happening in the backcountry. It has been five days since the last natural avalanche was reported. But for the past six days there have been multiple reports human triggered avalanches on northwest through easterly slopes steeper than 35 degrees. The key to safety is to use your best safe travel and route finding skills or avoid these areas.

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

The avalanche danger is CONSIDERABLE today on west through north, and north through east facing slopes steeper than about 35 degrees. You may also encounter an elevated avalanche danger on wind loaded slopes in upper elevation areas. On southerly slopes and slopes less than about 35 degrees, avalanche danger is generally MODERATE. Backcountry travelers may still want to avoid traveling under steep slopes or in gullies and other terrain traps.

Mountain Weather:

An upper level low rotating through a broad trough is producing easterly flow over the Wasatch this morning. Today this closed low will continue to move off to the east bringing cooler temperatures and some high clouds. Temperatures today will rise to near 20 degrees at 8,000’ and into the low teens at 10,000’. Skies will be partly cloudy and the winds will be from the east in the 15 mph range. The flow will shift back to the west by Tuesday morning. A weak short wave trough should move through northern Utah on Wednesday, with a stronger system forecast for the end of the week.

Wasatch Powder Bird Guides will be examining the snowpack stability throughout their permit area today. They will be moving around a lot and probably won’t linger in any one place for too long.

General Information:

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.

Bruce Tremper will update this advisory by 7:30 on Tuesday morning.

Thanks for calling!

________________________________________________________________________

National Weather Service - Salt Lake City - Snow.

For an explanation of avalanche danger ratings:

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