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.

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AVALANCHE ADVISORY

Friday, March 16, 2007  7:30 am
Good morning, this is Brett Kobernik with the Forest Service Utah Avalanche Center with your backcountry avalanche and mountain weather advisory.  Today is Friday, March 16, 2007 and it’s 7:30 in the morning.

 

Avalanche Watch: 

An avalanche watch is in effect for all the mountains of northern Utah.  This means we are expecting avalanche conditions to become more dangerous today and through the weekend.  A weaker then average snowpack coupled with a dramatic warming trend has been producing large and dangerous avalanches over the last 5 days.  This trend is expected to continue with warm temperatures over the weekend.  Steep slopes and areas below any steep slopes should be avoided.  People without excellent backcountry avalanche and route finding skills should stay out of the backcountry today through this weekend.

 

Special Announcement:

UDOT is planning on closing the highway in Little Cottonwood Canyon from entry 4 at Snowbird through the town of Alta at around 4:45pm today to do avalanche control work with explosives.  This includes the main road as well as the bypass road.  Interlodge restrictions will be in place by around 5.  People should clear the south facing ridges and slopes from Mt Superior up to Grizzly Gulch by around noon in the event that control work needs to be implemented earlier.  This work will also be performed Saturday afternoon as well.

Current Conditions:

Temperatures dipped below freezing at many locations last night which should produce a fairly decent surface re-freeze of the snow.  Keep in mind that there are lots of stations that recorded temperatures above freezing as well.  Some are Snowbasin Wildcat at 7800’, low of 37;  Tom’s Hill in Big Cottonwood at 9000 feet, low of 32 currently 35;  Davis Peak south of Provo Canyon at 9700 feet, low of 32 currently 35.  Winds are generally less then 10 mph from the west gusting into the mid 20s at the more exposed locations.

 

Snow and Avalanche Discussion:

Avalanche activity reported from yesterday was, oddly enough, from within ski resort boundaries in open areas in two separate incidents.  One ski patroller in Big Cottonwood canyon was taken by surprise when a northeast facing slope at around 9800 feet released a slab that took him for a ride.  Luckily, he wasn’t buried and sustained minor injuries.  It’s important to note that the surface was still firm and hadn’t become damp or unsupportable at the time.  There were also un-confirmed reports of another slide at a ski area in Little Cottonwood where no one was caught.  The point here is that if professionals who deal with snow on a daily basis are getting caught off guard, backcountry recreational users have equal or lesser odds.  While I was digging around yesterday it was easy to punch through the superficial re-frozen surface and reach down into the damp faceted snow which is not re-freezing.  You’ll find similar situations today in many areas.  (I have more photos of recent avalanches which I’ll post by around 9:00 am)

 

The main concern again is warming temperatures weakening the snow surface to the point where it fails or to the point where the faceted underlying snow fails as the slab above it becomes weak and can no longer resist gravity.  The key to backcountry travel is to get off of steep slopes before they become soft.  If you can stick your boot through the snow surface, you’re too late.  Also, keep in mind that even a supportable surface may not provide you with 100 percent protection as was the case with the patroller in Big Cottonwood.  Its best give slopes some extra lee way and get off them earlier then usual.  Southeast facing slopes are the first to soften therefore should be the first to move off of as the morning progresses.  South facing slopes are next then southwest and west as the sun swings around in the afternoon.

 

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: 

Today we’ll see mostly clear skies with ridgetop temperatures around 40 and in the low 50s at 8,000 feet.  Winds will be from the west in the 5 to 15 mph range.  Warm temperatures headline the weather news through the weekend with more of the same and little if any refreeze the next couple of nights.  The next system is expected sometime Tuesday when temperatures will cool off and bring the next chance for snow.

 

Announcements:

Yesterday, Wasatch Powderbird Guides flew in American Fork, and the Sessions. Today they’ll be in American Fork, White Pine, Snake Creek, the Sessions and Cascade.  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.
To sign up for automated e-mails of our graphical advisory click HERE

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.

Evelyn Lees will
update this advisory by 7:30 on Saturday morning, and thanks for calling.