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, Monday January 28, 2008

Hello and good morning, this is Toby Weed of the Utah Avalanche Center with your Logan Area backcountry avalanche and mountain weather advisory.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry.com.

We are continuing a Special Avalanche Advisory through tonight for the mountains of Northern Utah.  A powerful Pacific storm system with strong winds and heavy snow will create widespread dangerous avalanche conditions in the backcountry.  Avoid steep slopes and obvious or historic avalanche terrain in the backcountry.

Current Conditions:

Well, at least it didn’t rain yesterday.  It didn’t snow either and instead turned into a rather nice day.  The incessant southwest wind picked up in intensity even more yesterday afternoon, posting sustained hourly averages at the CSI weather station in the 40+ mph range, with gusts in the mid to upper 70s.  It’s snowing heavily this morning in the Bear River Range. You can expect heavy snowfall and continued strong winds throughout the day, swinging around from the west with frontal passage.  You should stay out of avalanche terrain in the backcountry during today’s storm, as the avalanche danger will rise dramatically.  Sizable natural and triggered avalanches will become likely as wind-drifted snow rapidly piles up on steep slopes with existing weak layers.

Avalanche Conditions:

We noted fairly widespread wet avalanching at lower elevations in yesterday’s warmth.  One slide came down the fire-ravaged slope above First Dam, inflicting some property damage and stopping within a couple hundred feet of the river. More wet avalanches may be possible this morning, but the biggest danger today will come from wind deposited heavy snow which is piling up on weak snow that was on the surface last week. I was able to crack out a couple small soft wind slabs yesterday on a west northwest facing sub-ridge at around 7300’.


It seems like southwest winds have been howling for days in the mountains, and gradually they’ve intensified to outrageous.  The wind caused extensive drifting and built hard and soft slabs on numerous steep slopes at all elevations.  The biggest problems are likely to be found at upper elevations, near ridge tops, and on slopes facing the northern half of the compass.  Hard and soft slabs could be up to 2’ deep and may be quite sensitive, as many formed on weak surface snow.  Watch for smooth chalky looking or hollow sounding drifts on steep exposed slopes and cross-loaded slabs in and around terrain features like gully walls, rolls, sub-ridges, and cliff bands. Obvious drifts however, will become obscured today by rapidly accumulating new snow.

Rapid accumulation of heavy snow on top of existing weaknesses will likely cause a dramatically increasing danger on all steep slopes in the backcountry. Heavy snowfall combined with strong winds leads to extensive loading over large areas, often depositing tons of snow onto slopes well off ridge lines. This may become a serious issue by mid-afternoon.  As significant snowfall piles up on steep slopes and avalanche starting zones, the danger will become much more widespread.

Bottom Line:

There’s a CONSIDERABLE danger and you could probably trigger wind slab avalanches on many drifted slopes steeper than about 35 degrees in the backcountry.  This morning, you’ll find the most danger on steep upper elevation slopes facing the northern half of the compass.  With heavy snowfall and strong winds in the forecast, expect the danger to rise significantly and become much more widespread throughout the day.  The danger will probably rise to HIGH during the day, and significant natural and triggered avalanches will be likely.  You should avoid travel in backcountry avalanche terrain.

Mountain Weather:

The National Weather Service has continued a Winter Storm Warning through 10:00 tonight. Expect heavy snowfall and strong westerly winds to continue throughout the day, and we should pick up a solid foot by late tonight. Some lightning is possible with frontal passage around mid morning.  Another fairly strong storm is expected to impact the region tomorrow and tomorrow night. And several more storms are lined up with their sights set on Northern Utah.

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.

The second annual avalanche awareness ride is Saturday Feb. 2nd and we’d love to see all of you there!  Proceeds help to support snowmobile specific avalanche awareness projects. Details can be found at http://www.avarides.com/

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.