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

Saturday February 4, 2006

Hello and good morning, this is Toby Weed of the Forest Service Utah Avalanche Center with your Logan area backcountry avalanche and mountain weather advisory.  It's Saturday February 4th at 7:00 am.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from avalanchetools.com.

Mountain Weather:

Southwesterly winds will pump warm air into the region today, and high clouds could be thin enough for long-wave solar radiation to be a factor.  It could get pretty warm, even at higher elevations.   A quick-hitting storm, entering the region late this afternoon, will drop 8-10 inches of fairly light powder overnight before moving on out by Sunday morning.  There's a slight chance for more snowfall on Monday, but a high pressure will  build in the upcoming work-week.

Current Conditions:

Strong northwest winds damaged the snow in exposed terrain at upper elevations yesterday.  The wind ripped snow off windward slopes and built deep stiff drifts in fetch areas.  Yesterday in lots of exposed areas, you could easily walk on the hard scoured or drifted snow surface, hardly leaving a mark.  In fact in some places, you really had to dig your toes in just to stand up.  The copious new snow from last week, (over 5 inches of water at Tony Grove) is mostly supportable, allowing for good floatation.  Today you'll find easy trail-breaking and riding conditions almost anywhere and the best powder snow on sheltered mid-elevation slopes. 

There's 126 inches of snow on the ground at the Tony Grove Snotel site and 161 percent of normal water content.  It's currently 21 degrees at Tony Grove and 20 at 9500' at the Campbell Scientific weather station atop Logan Peak.  Ridge-top southwesterly winds are in the 15-20 mph range and are likely to increase ahead of the approaching storm.

Avalanche Conditions:

Yesterday's wind built sensitive wind-slabs on east and south facing slopes, and it cross-loaded drifts into fetch areas like gullies, rock outcroppings, and sub-ridges.  I triggered significant shooting cracks in a big drift on a low-angled east facing slope at about 9000'.  Respectful of the potential for ugly hard-slab avalanches elsewhere, I gave the stubborn drifts a lot of room.  Hard slabs have a tendency to sometimes let you get well out on them before releasing.  Although I suspect that these drifts are better bonded and less active today than yesterday, you should be wary of chalky looking, hollow sounding, and stiff feeling wind deposits on steep slopes.  East and southeast facing slopes received the most loading, and some of these have a suspect buried layer consisting of weak sugary snow associated with a thin sun-crust. 

If the sun's warmth is trapped by some high clouds today, rapid warming caused by green-housing could easily be an issue.  Very warm temperatures fed by a southerly wind are likely even at high elevations.  As all the fresh new snow is initially warmed, the surface could get saturated, and wet avalanches will be increasingly possible.  Spontaneous roller balls or wet activity are signs of increasing danger, and you should move off slopes that get moist and sloppy.

Bottom Line:

There's a MODERATE danger in the backcountry, with avalanches possible on wind-drifted slopes steeper than about 35 degrees.  Avalanches on some steep slopes could step down into buried weak layers and be large and dangerous.  With warm temperatures and a possible greenhouse effect, the danger of wet new-snow avalanches could rise to MODERATE on steep slopes with saturated surface snow.

General Information: 

For a list of our upcoming classes and awareness talks, go to our Education page . For a list of recent avalanches in  the regional backcountry go to Avalanche List.  Snow nerds, check out the new Snow Profiles page.  You may enjoy our Images Page.

Please send backcountry observations to [email protected] or leave a message at 755-3638, especially if you see or trigger an avalanche in the backcountry. We really want to hear from you, even if you think your observation is unimportant.    The information you provide may save lives...

 I will update this advisory again on Sunday morning by about 7:00.

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. 

National Weather Service - Salt Lake City - Snow.