Wasatch-Cache National Forest:  In partnership with:  Utah State Parks and Recreation, Friends of the Utah Avalanche Center-Logan, and Utah State University College of Natural Resources.


       The Utah Avalanche Center Home page is: http://www.avalanche.org/~uac/

             (click on) Utah Avalanche Center in Logan for our home page           


Logan area Avalanche Advisory

7:30, Sunday February 3, 2008

Hello and good morning, this is Toby Weed of the Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  It’s Sunday February 3rd, at 7:30 in the morning.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from the Trailhead.

We are issuing an Avalanche Warning for the mountains of Northern Utah.  Natural avalanches are likely on a variety of slopes at all elevations in the backcountry.  Avoid and stay well out from under steep slopes and obvious or historic avalanche paths.

Current Conditions:

 A powerful storm with heavy snowfall and strong south and southwesterly winds will make travel quite dangerous in the backcountry today, and you should avoid avalanche terrain. While nice powder could be found in many areas this weekend, we’ve received reports of numerous human triggered avalanches and close calls.  Might be a good idea to hit the lifts or at least stay in mellower (lower angled) terrain. 


  Avalanche Conditions:

Numerous reports of a very active day in the Utah backcountry are filtering into the Utah Avalanche Center this morning, with several triggered avalanches, some stepping into old snow and a handful of people taking unintended rides. Locally, I have reports of a couple spooky human triggered avalanches from this weekend.  Just as we thought, recently deposited stiff wind slabs are clearly still sensitive to human weight.  We’ve observed evidence of numerous natural and a few triggered wind slab avalanches in the backcountry over the last week.  I’ve posted pictures of a few on the images page.  The reports and observations are mainly from lower and middle elevations, and there have been recent local avalanches on a wide variety of slopes facing most directions and at all elevations.  On Friday we ventured into a lower elevation area in the Southern Wellsville Range where widespread natural avalanching occurred overnight, (photos).   A skier triggered an avalanche on a drifted north facing slope at around 6300’ in the foothills south of the mouth of Green Canyon on Friday that was reported to be around a foot deep and a couple hundred feet wide.  The avalanche ran around a thousand vertical feet before stopping within a stones throw of the road to the trailhead.  And, yesterday a skier fell at around 8300’, triggering a 3’ deep slab avalanche in “the Gut” of the popular east facing bowls in the Garden City Canyon/Swan Peak Area.  The lucky skier escaped injury after a short ride.

The winds picked up from the south again overnight and are gusting close to 50 mph this morning.  Freshly built wind slabs will surely be an issue again today, and heavy snowfall accompanying strong winds may well lead to extensive loading over large areas often quite a ways off ridge lines.  The incoming powder will obscure many drifts, and last week strong southwest winds caused extensive drifting and built hard and soft slabs on numerous steep slopes across the region. Now these are buried and hidden.  The biggest recent wind deposits are at upper elevations, near ridge tops, and on slopes facing the eastern half of the compass, but there are significant stiff drifts at all elevations and on slopes facing all directions. Watch for cross-loaded slopes where drifts piled up in and around terrain features like gullies, cliff bands, and sub-ridges

 Wind-drifted snow overloaded some steep slopes with existing persistent weak layers.  There is potential for some avalanches to step down to one of several lingering weak layers formed on the snow surface before last week.  These now buried weaknesses consist of thin sugary or faceted layers located under brittle sun crusts on some slopes and including frost crystals or surface hoar on others.  In areas with a shallow overall snowpack some avalanches could step all the way down to sugary depth hoar near the ground.

   Bottom Line:

There is a HIGH danger in the backcountry today, and natural and triggered avalanches are likely on a variety of steep slopes and at all elevations during periods of strong wind and heavy snowfall.  In some areas, wind-drifted snow overloaded slopes with existing persistent weak layers, and the danger will remain CONSIDERABLE for a while even after the storm departs.  Avoid and stay well out from under steep slopes and obvious or historic avalanche paths…

    Mountain Weather:

The National Weather Service has issued a Winter Storm Warning for the mountains around Logan through Monday morning.  Expect 10-20 additional inches of accumulation and strong south and southwesterly winds today.  The next smaller Pacific storm will affect mainly Northern Utah on Tuesday night into Wednesday, and ridging or a break in the storms is expected later in the week.

General Announcements:

Check out photos of avalanches in the Logan Area on our images page.

       Go to the Avalanche Encyclopedia if you have any questions about terms I use in the advisory.

I'm very interested to know what you're seeing out there.  Please e-mail observations to me at [email protected] or leave me a message at 755-3638, especially if you see or trigger an avalanche in the backcountry. We keep all observations confidential.

This advisory will expire in 24 hours from the posting time.

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.