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Logan area Avalanche Advisory

Saturday December 22, 2007

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 December 22nd and it’s about 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:

It will be a beautiful and powdery day in the backcountry, but it will also be quite dangerous in avalanche terrain. With Christmas right around the corner and triggered avalanches likely, today will be a good time to play it safe. I recommend staying in the meadows and flats and well away from the steeper upper elevation hills until the unstable snow heals with time. Beaver Mountain opens today, so you can ride the lifts and avoid the danger. It’s currently zero degrees at the Campbell Scientific weather station at 9400’ on Logan Peak, and there is no wind to speak of. It’s 5 degrees at Tony Grove Lake with 42 inches of total snow on the ground at the Snotel site. You will not be able to drive far up the Tony Grove road due to very deep snow and 2 illegally plowed snow piles blocking the way.

Avalanche Conditions:

The good news is that we’ve finally had a widespread avalanche cycle in the region that cleaned out all the weak snow on numerous suspect slopes. Most of the naturals occurred Thursday evening during the most intense part of the furious storm. Yesterday, from south of Tony Grove Lake we could see evidence of a number of large avalanches on slopes facing southeast through north and above 8000’. Poor visibility limited our view of more distant paths but it was clear the cycle was quite extensive, including slopes that I have not yet seen avalanche. Like “P-tex Bowl” in the Polygamy Cave area off point 9248 on southern Cornice Ridge. Here, I looked at the 400+’ wall-to-wall crown where new snow broke out 2 to 4 feet deep on sugary facets that formed in mid December. Looking back down the ridge, I noticed that the entire north facing bowl in the ridge top saddle due south of the lake also had avalanched. I could also see a few very broad avalanches on hills north and west of the lake, including rarely active southeast facing slopes. We triggered several very large heart stopping audible collapses or woomphing noises on untracked low angled terrain, both in north and south facing areas. And, just to show that red flags or obvious clues do work as avalanche predictors, my partner remotely triggered an avalanche on a north facing slope even as I was examining the “P-tex” crown.

The bad news is that triggered avalanches are probable today on slopes where significant new snow stacked up on preexisting weak snow. The problem was exacerbated by wind drifting, and winds accompanying periods of high precipitation rates led to extensive loading over large areas and well off ridge lines. Soft and stiffer slab avalanches consisting of new snow in the 2 to 3 foot deep range remain likely today. Pay attention to obvious signs of instability like recent avalanches on similar slopes, collapsing or woomphing noises, cracking, or hollow sounding snow, and be willing to reassess your route.

Bottom Line:

Overall there’s a CONSIDERABLE avalanche danger in the backcountry today, with triggered avalanches probable on many slopes steeper than about 35 degrees and above around 8000’ in elevation. Although natural avalanches are generally unlikely, dangerous human triggered avalanches are quite likely this weekend. Warranting pockets of HIGH danger on upper elevation wind drifted slopes facing northwest through southeast. Continue today to avoid steep slopes and obvious avalanche paths or run-out zones.

Mountain Weather:

A weak storm will brush by northern Utah tonight and tomorrow morning, bringing a threat of around 4 inches of snowfall to the Central Bear River Range. A much stronger and colder system is expected to affect the region on Christmas Eve, challenging Santa’s navigational skills. Yet another storm will be right on his heels, scheduled for Wednesday-Wednesday night.

General Information:

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.