Wasatch Cache National Forest
In partnership with: Utah Division of State Parks and Recreation, The Friends of the Utah Avalanche Center, Utah Department of Emergency Services and Homeland Security and Salt Lake County.

“keeping you on top”

AVALANCHE ADVISORY

Thursday, March 15, 2007  7:30 am
Good morning, this is Bruce Tremper with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Thursday, March 15, 2007 and it’s 7:30 in the morning.

Current Conditions:

Thankfully, cooler air pushed in overnight dropping the ridgetop temperatures down to just below freezing and about 25 degrees on the highest peaks.  With high and mid level clouds overnight to help hold the heat in, the snow surface probably did not refreeze as much as you would expect with the cooler air temperatures, but I’m guessing you will find supportable snow until about noon today.  Almost all slopes are heavily sun crusted with the exception of a few scraps of powder on upper elevation north facing slopes.

 

Snow and Avalanche Discussion:

Yesterday, the wet slab activity behaved itself much better than the sweltering days of Monday and Tuesday because temperatures were 5 degrees cooler and a moderate wind helped cool the snow surface.  As a result there was only two, large, wet slab reported.  The first was yet another wet slab in the backcountry of Alta on Emma Ridge, a steep, south-facing slope near Grizzly Gulch.  It released naturally in the heat of the afternoon and the debris ran to within 200’ of the road. Second, yesterday at mid day, someone kicked a cornice near Farmington Peak and broke out a deep, wide, wet slab below. Also of interest, yesterday I investigated the huge, natural, wet slab from late Tuesday afternoon on the northwest face of Gobbler’s Knob and I have PHOTOS posted, which are definitely worth a look.  If you are an avalanche geek, you definitely need to make time today to go up and admire the spectacle.  The debris is at least 30’ deep in the aspen-flats at the bottom and you should update your photo collection with textbook-characteristic, wet avalanche behavior as is forms its own 30’ deep bobsled run as it descends, wiping out all the vegetation in its path.  For an old avalanche geek like me, yesterday made my year.

Today, the cooler temperatures will keep most of the deep, wet slab activity to a minimum in the morning, but by afternoon, it will heat right back up to above freezing conditions and we could see more wet slabs.  Also, remember that the refreeze is quite shallow and superficial and many places have noting but wet mush underneath, so we may see some “corn slabs” today as a seemingly frozen and solid surface releases as a wet slab avalanche. 

More importantly, temperatures will rise rapidly to sweltering, bikini weather for the weekend.  Last night will be the last refreeze for the next few days and ridge top temperatures will rise to the mid 40’s by Saturday with 55 degrees at 8,000’.  In other words, we will have a scary weekend of huge, wet slab avalanches on all aspects.  UDOT will close the Little Cottonwood Canyon road between Alta and Snowbird for a short while on Friday afternoon for avalanche control.

 

Bottom Line for the Salt Lake, Park City, Provo and Ogden area mountains: 

The danger of wet sluff and slab avalanches is MODERATE this morning and will rise to CONSIDERABLE again today on and below slopes of about 35 degrees and steeper, with daytime heating and sun.  Slides can be triggered on slopes of all aspects and elevations.  CONSIDERABLE means human triggered avalanches are likely and natural avalanches are possible, so stay off of and out from under steep slopes this afternoon and through the weekend. 

 

Mountain Weather: 

With mostly sunny skies, temperatures will rapidly rise today, especially in wind-sheltered areas.  Ridgetop temperatures will be around freezing with a 20 mph wind from the west.  Friday morning, ridge top temperatures will rise to 37 degrees and to the mid 40’s on Friday night and through the weekend.

 

Announcements:

Yesterday, Wasatch Powderbird Guides flew a few corn runs in American Fork, and today they will be looking for corn in American Fork, the Sessions, Cascade and White Pine.  For more info, call 742-2800.

 

The UAC and ACE are offering a day long Women’s Avalanche Awareness class at Alta on March 22nd covering beacon use and basic safe travel, terrain and snowpack information, for a nominal fee.  For more details go to: www.altaarts.org.

 

Listen to the advisory.  Try our new streaming audio or podcasts

UDOT highway avalanche control work info can be found HERE or by calling (801) 975-4838.

Our statewide tollfree line is 1-888-999-4019 (early morning, option 8).

For a list of avalanche classes, click HERE
For our classic text advisory click HERE.
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We appreciate all the great snowpack and avalanche observations we’ve been getting, so keep leaving us messages at (801) 524-5304 or 1-800-662-4140, or email us at [email protected]. (Fax 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.

Brett Kobernik will update this advisory by 7:30 on Friday morning, and thanks for calling.