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, December 25, 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 Wednesday, December 25, 2002, and it’s 7:30 in the morning.

 

Current Conditions:

Overnight temperatures dropped to near zero along the upper ridgelines and into negative numbers in the mountain valleys.  The winds have been from the west and northwest in the 10 mph range.  Along the highest ridgelines the winds have been in the 20 mph range with some gusts over 30 mph.  Santa brought us all a white Christmas with about a half inch of new snow in most locations and 3 to 6 inches in the Ogden Mountains!

 

The backcountry snow surface is a mix of surface hoar and near-surface facets on top of wind slabs or old faceted snow.  Many areas remain punchy, with a firm upper layer that you can break through.  Areas below 8,000’ generally have a thin snowpack, which makes for easy traveling.

 

Avalanche Conditions:

It has been a week since our last major snow event, but the snowpack is taking its own sweet time adjusting to the load.  To complicate things, southeast winds on Monday built wind drifts in odd places, and last night the westerly winds were also strong enough to transport snow.

 

We continue to receive reports of human triggered avalanches from the backcountry.  Yesterday an avalanche was triggered on the northeast side of Sunset Peak.  The slide was about 2 feet deep and ran down into the flats.  There was also an avalanche reported in the Cabin Shot on Gobblers Knob.  The slide was triggered on a north and northeast facing wind roll.  It initially broke about 2 feet deep and 75 feet wide, but pulled out several other pockets on the way down.

 

To sum things up there are several different kinds of avalanche dragons to look for today.  The first is a deep instability due to buried faceted snow.  Keep a lookout for this dragon on northwest though east aspects that are steeper than about 35 degrees.  There are also dragons lurking in wind drifts built by southeast winds on Monday.  And lastly there are wind drifts built by west and northwest winds overnight.  Yesterday the snow surface was covered with hoar frost or surface hoar.  Wind drifts sitting on this layer will be quite sensitive today.  We are beginning to see repeater slides.  Wind drifts in paths that avalanched last week should be approached with caution today.

 

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

The avalanche danger is CONSIDERABLE today on northwest, north, northeast, and east facing slopes 35 degrees or steeper and on steep slopes with recent deposits of wind drifted snow.  On southerly facing slopes and low angle slopes the avalanche danger is generally LOW. 

 

Mountain Weather:

A weak short wave trough is moving through northern Utah this morning.  Snow showers should continue through mid day and break up in the afternoon.  Snow accumulations in the 3 inch range are expected.  Temperatures today should rise to near 20 degrees at 8,000’ and to near 10 degrees at 10,000’.  Winds will be from the west and northwest in the 15 mph range.  Another weak short wave will move through tomorrow and a stronger storm is forecast for the weekend.

 

General Information:

Wasatch Powderbird Guides will not be flying today.

 

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 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