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

 December 16, 2006

Hello and good morning, this is Toby Weed of the Utah Avalanche Center in Logan with your backcountry avalanche and mountain weather advisory.  It's Saturday  December 16th, and it's 7:00 in the morning.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from EK .

Current Conditions:

Thursday's rain up to around 8500' saturated the surface snow, and subsequent freezing created a super-hard and strong ice-crust.  The crust is so strong, it easily supports the weight of a snowmobile at Tony Grove Lake, and so thick I couldn't  even stand on it.  I slid down to the lake twice while examining some large natural avalanches on the west side.  The Snotel site at Tony Grove picked up about 5 inches of nice snow overnight, bringing the total on the ground up to 45 inches with 10.8 inches of water equivalent.  We picked up around 4 inches of water at the site in the last four days, and it now sits at 109% of average for the date.  The wind is from the north at 5 mph, and it's 1 degree at the Campbell Scientific weather station on Logan Peak.  It's down to10 degrees at 8500'.

Avalanche Conditions:

The first thing I noticed besides the slick crust when I got up to Tony  Grove Lake yesterday were the four sizeable natural avalanches from Thursday across and on the west side.  A couple of these, which had pulled out under the steep cliffs above, ran way out onto the ice of the lake.  I found that the ice-crust, which is now holding the snowpack together down low, disappears when you get up up to higher elevations. At one point on a low angled north facing slope, I triggered a heart-stopping audible collapse.  I talked to one party, which described initiating several of these whoomphing sounds as well as simultaneous shooting cracks.  These are obvious signs of instability, and if you encounter such conditions today you should think twice about entering any steep slope.  The same party intentionally triggered a sizable hard slab avalanche in upper Bunch Grass Canyon with a cornice drop (pictures).  Apparently, the cornice broke unexpectedly and a little farther back than expected, sending one member of the party on a little elevator ride.  Thankfully, the slope avalanched before he hit it, and he neatly landed on the fresh, two-foot-deep crown and watched as the slope slide below him.  Although the snow pack is adjusting to its new load, a thick slab was recently deposited on weak sugary layers that we call persistent weak layers.  On many slopes the situation is still unstable, and the slab is sitting there in a spooky balanced state, with a trigger the only thing keeping it from avalanching.

Bottom Line:

There is a CONSIDERABLE  avalanche danger at upper elevations in the backcountry. Triggered slab avalanches are probable on northwest through southeast facing slopes steeper than about 35 degrees and above about 8500'.  At lower elevations, below 8000' where rainfall created a thick ice crust, the danger is LOW

Mountain Weather:

The National Weather Service has the mountains of Northern Utah under a Winter Storm Warning through 5:00 am Sunday morning, but it doesn't look like we'll get as much snowfall as the mountains in the central part of the state.  The point forecast only gives us a couple inches with this, but we are likely to pick up around 4 to 6 inches at higher elevations overnight tonight.

General Information:

 The Tony Grove Road is not maintained in the winter, and the heavy wet snow in the last couple days probably shut down wheeled access to the area near the lake.  You should be prepared to get stuck in a couple feet of snow if you try to head up this weekend.  Turning around may be difficult.    Rumor has it that Beaver Mountain will open up next week.

  The Friends of the Utah Avalanche Center-Logan will present the 3rd annual fundraiser on Friday, January 19th at the Bullen Center in downtown Logan.

 I'll update my advisories on Tuesday and Thursday evenings and weekend mornings by about 7:00.   I will update this advisory again on Sunday morning.  Logan Area advisories will be accessible through the new statewide toll-free avalanche info line; 1-888-999-4019.

  Please  send backcountry observations to [email protected] or leave us a message at 755-3638, especially if you see or trigger an avalanche in the backcountry.

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.