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.


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Logan area Avalanche Advisory

7:30, Saturday February 2, 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 Saturday February 2nd 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 Import Auto.

Current Conditions:

 Powder conditions vary across the region.  We found some nice graupel-filled and inverted snow at low elevations yesterday and fairly difficult trail breaking.  You’re likely to enjoy today’s settled–out and slightly re-crystallized version a bit more.

The Tony Grove Snotel reports approximately 4.5 inches of water equivalent gain in the last week, and there’s 92 inches of total snow on the ground now containing 94% of the average water content.  The wind on Logan Peak has been fairly light in the last 24 hrs, now come around from the southwest and averaging under10 mph. It’s currently 4 degrees at 9400’.


  Avalanche Conditions:

We’ve observed evidence of numerous natural and a few triggered wind slab avalanches in the backcountry over the last week.  Yesterday we stumbled into a lower elevation area in the Southern Wellsville Range where widespread natural avalanching occurred overnight, (photos).

For a few extended periods last week strong southwest winds caused extensive drifting and built hard and soft slabs on numerous steep slopes across the region.  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.  Much of the quick healing instability associated with new snow will probably already have settled out by now, but 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.

   Bottom Line:

There is generally a MODERATE danger in the backcountry, and triggered slab avalanches are possible on steep slopes at all elevations.  In some areas, wind-drifted snow overloaded slopes with existing persistent weak layers, and the danger will remain CONSIDERABLE.   You could probably trigger aging wind slab avalanches on a good number of slopes steeper than about 35 degrees in the backcountry.  Lingering persistent slab avalanches are most likely at upper elevations and on slopes facing the eastern half of the compass.  Use good snow assessment and safe travel techniques to minimize your risks today.  The danger will likely rise and become more widespread tomorrow with another Pacific storm and potential for heavy snowfall and strong winds.

    Mountain Weather:

The National Weather Service issued a Winter Storm Watch for our area for late tonight through Monday morning.  Snowfall is expected to develop late tonight in Northern Utah and last through Sunday.  Some potential for accompanying strong westerly winds for the mountains, but much of the energy is aimed at the Central and Southern Mountains.  Another storm will affect mainly Northern Utah on Tuesday into Wednesday, and then probable ridging and a possible break in the long stream of recent Pacific storms.

General Announcements:

We’ll see you today up at Winter Trails Day at the Hardware Ranch TH up in Blacksmith Fork.

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.