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

Sunday, February 04, 2007  7:30 am
Good morning, this is Drew Hardesty with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Sunday, February 04, 2007 and it’s 7:30 in the morning.

Current Conditions:

Nothing like a little wind to wreak havoc with things.  The winds remained strong from the west northwest overnight blowing 20-30 gusting to near 40 with the highest anemometers recording sustained hourly averages into the 40’s and 50’s with gusts into the 70’s.  Overnight lows dipped just into the mid twenties and upper teens and the cloud cover from an exiting disturbance to our northeast should dissipate into partly cloudy skies.  The strong winds have added flavor to most terrain and the best riding conditions will be found on sheltered mid elevation slopes.

 

Snowpack and Avalanche Conditions:

In an avalanche accident that made most of the news outlets yesterday, two snowshoers ascending the east ridge of the Pfeifferhorn triggered a small hard slab that swept them down the southeast flank of the peak and over 150’ worth of cliff bands.  One man was reported to be in critical condition.  My preliminary accident report can be found here.  Wasatch Backcountry Rescue, both Utah and Salt Lake County sheriff’s department, and the air ambulances pulled off an amazing rescue.  Good work. 

 

I received numerous reports of human triggered slides in the backcountry yesterday on a variety of aspects and elevations.  Many triggered slides of just new wind drifts, while others triggered slides into older faceted snow.  One party skiing off the northeast facing side of Scott Peak along the Park City ridgeline had the 4th skier trigger a hard slab reported 3’ deep and 65’ wide, engulfing one of the other skiers waiting down below and burying him to his chest.  Another skier down on the north side of Timpanogos remotely triggered three avalanches on faceted snow up to two feet deep and 400’ wide.  These were triggered from up to 50’ away, breaking on steep wind-loaded east facing slopes at about 9000’.  Another slide included a collapse failure of a facet-crust sandwich 12-18” deep and 50’ wide in upper Wilson Glade, a steep north facing slope above Mill Creek at around 10,000’.  On the exit, the skiers triggered a small drift that gouged down into the older faceted snow, running over 1000’ and within 50 yards of the Mill Creek Road.  My own party collapsed a couple steep wind loaded slopes and safely triggered a few shallow slabs in the new snow.  Photos of these and other avalanches can be found on our photos page here.  You can also call our more detailed line at 1-888-999-4019 and hit option 8 to get more info.  The avalanche list will be updated by mid-morning.

 

We’ve been waiting and waiting for a weather event to stir things up and it finally arrived.  With a very weak snowpack structure, all it took was a few inches of snow late in the week and strong winds to produce widespread avalanching.  While things today may be slightly less sensitive, multiple avalanche issues persist in steep wind loaded terrain.  Cornices will continue to be sensitive and will break back farther than expected.  Hard slab avalanches, drifts that will allow multiple tracks on the slope before pulling out, remain.  Remotely triggered avalanches, avalanches that may be triggered at a distance, will still be possible.  Even the cagiest avalanche folks can be surprised by these two phenomena and neither are very reactive to common tactics like slope cuts or cornice drops.  They’re unmanageable.  It’s the type of scenario that’ll let a party ski a slope, and then remotely release on their uptrack.  If you’re looking for clues to instability, it’s recent avalanches, check….collapsing of the snowpack, check………shooting cracks, check.  Sure it’s another day for things to settle out, but it’s like saying the grizzly bears are a little less cranky than they were yesterday.  The current structure may be slower to heal than storm snow or your garden variety wind drifts. 


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

Today, the avalanche danger is MODERATE with pockets of CONSIDERABLE on any slope steeper than about 35 degrees with recent drifts of wind blown snow.  The rating reflects the complexity of the types and patterns of the avalanches and human triggered avalanches will still be possible.  The strong winds loaded a variety of aspects and elevation, so any slope should be considered guilty prior to cross-examination.  Watch for some wet sluffing on the steep sun-exposed slopes by late afternoon.

 

Mountain Weather: 

Skies will start to clear by late morning with daytime highs reaching into the mid-thirties at 8000’ and mid-to upper twenties at 10,000’.   The strong west to northwest winds will continue to blow 25-30+ mph along the high ridgelines, but should lose some steam by late afternoon.  High pressure builds for the early part of the week, with a change in the pattern by the weekend.

Announcements:

Yesterday, the Wasatch Powderbird Guides did not fly, but today they’ll try to get out to AF, the Sessions, Snake Creek, and the Cascade Ridgeline. With questions regarding their areas of operation call 742-2800.

On February 8th at 7:30, there will be a Teton Skiing documentary at Brewvies.  Details are below, or click here for more information.

 

Sad news:  Thursday, Ed LaChapelle, considered the grandfather of American avalanche research, died while attending the memorial service of his ex-wife and good friend, Dolores LaChapelle in Silverton, Colorado.  He died while skiing.  Ed did most all of his pioneering avalanche research at Alta from the early 1950’s until the early 1970’s.  He will be missed. For more information, click below.

 

http://www.newwest.net/index.php/city/article/avalanche_pioneer_ed_lachapelle_dies/C101/L101/

 

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

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

 

Our new, state wide tollfree hotline is 1-888-999-4019.
(For early morning detailed avalanche activity report hit option 8)

For a list of avalanche classes, click HERE

For our classic text advisory click HERE.

To sign up for automated e-mails of our graphical advisory click HERE

We appreciate any snowpack and avalanche observations you have, so please leave us a message 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.

I will update this advisory by 7:30 on Monday morning, and thanks for calling.