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

 

 Tuesday  December 20, 2005                     

Hello,  this is Toby Weed of the Forest Service Utah Avalanche Center in Logan.  Itís Tuesday December 20th at 9:00 pm.   This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan, with help from avalanchetools.com your local on-line source for backcountry gear.

Current Conditions:

The freezing-rain or rime crust that formed on the snow surface today at higher elevations reminded me of East Coast snow conditions. Although it's always nice to get out, I thought the traveling conditions in the backcountry were horrendous.  First we got the truck stuck in icy slush as we pulled into the trailhead parking.  Then we got soaked all day by East Coast-like drizzle as we slogged through shin-deep very top-heavy snow.  We needed windshield wipers on our goggles, and rain-gear as opposed to the powder-shedding gear we wore.  We found trail-breaking both time-consuming and tedious.  The loud turning conditions through the forming crust were quite challenging...just like touring in Vermont.  Although we didn't want to push our luck riding off the groomed trail, we talked to experienced riders on mountain sleds who kept getting badly stuck.  They had trouble even on small hills, bogging down in the heavy snow  and digging in deeply as soon as their tracks started spinning down into the weak sugary old snow.

Avalanche Conditions:

Today we noticed a few recent localized natural slab avalanches above 8000', mostly on east  facing slopes.  As I took my turn breaking trail, I triggered a couple audible collapses or whoomfing noises, which are caused by a compressive failure of a weak layer overlain by a slab.  Many of our test pits showed very weak snow right under the now sticky, mashed-potato-like snow that's fallen since Saturday morning.  On lots of slopes in the region, a couple inches of light cold snow that fell near the end of last week nicely preserved a layer of frost crystals or surface hoar and small sugary grains called near-surface facets.  The localized natural avalanches we saw today occurred on slopes steeper than about 35 degrees where this weekend's storm drifted heavy moist slabs onto this weak surface snow.  If the rain-crust freezes up nicely tonight it could lock things up, but on some slopes the instability will probably linger for a few days.

Another problem is the warmth.  Tomorrow will be unseasonably warm, with high temperatures at 8500' forecast to reach well into the forties. What a difference from last week's arctic conditions.  This afternoon we noticed a number of wet avalanches visible from the road in Logan Canyon. Tomorrow's warm temperatures will cause a continuing danger of wet point release avalanches on steep slopes at lower and mid-elevations.  The warmth may also keep slab avalanche conditions active tomorrow, and you could still trigger 1 to 3 foot-deep avalanches on lots of previously wind-drifted slopes in the region. 

Bottom Line:

On Wednesday you'll find a CONSIDERABLE avalanche danger on slopes steeper than 35 degrees with significant deposits of previously wind-drifted snow.  Slopes above 8000' facing north through east with weak sugary underlying snow are the most suspect.  The danger is MODERATE and you might trigger avalanches on steep slopes even without obvious deposits of wind-drifted snow.  There will also be a CONSIDERABLE danger of wet point-release avalanches on steep lower and mid-elevation slopes with shallow overall snow-cover.

 Mountain Weather:

The moist Pacific flow will continue through the week.  Tomorrow, we'll have the best chance for a break, with warm temperatures, mostly cloudy skies and a chance of snow or rain showers.  Snow is in the forecast for Wednesday night and Thursday, with a stronger period of storminess predicted for Thursday night.  At this point, Christmas weekend looks to be partly cloudy with a flake or two possible.

General Information: 

 For a list of our upcoming classes and awareness talks, go to our education page

Snow nerds, check out the new Snow Profiles page.

Please send backcountry observations to [email protected], especially if you see or trigger an avalanche in the backcountry.

  This advisory will expire on Wednesday night.   But, I will update it again on Thursday night.

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. 

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National Weather Service - Salt Lake City - Snow.