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

 

 Sunday  December 18, 2005           

Hello and good morning, this is Toby Weed of the Forest Service Utah Avalanche Center in Logan.  Itís Sunday, December 18th 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 Import Auto at 502 W 1400 N.

Mountain Weather:

Well, it's a little warmer this morning, at least compared to what we've seen for the past week.  The temperature rose into the upper single digits at the Campbell Scientific weather station on Logan Peak.  As of 5:00 this morning it's reading 9 degrees, with a southwesterly breeze averaging in the mid-teens.  Overnight snowfall amounts at 8000' vary from about an inch at Franklin Basin (just north of the Idaho state line) to about 5 inches at Ben Lomond Peak (northeast of Ogden).  8500' high temperatures should stay just below 20 degrees today, and snowfall will intensify a bit tonight, with 6 additional inches possible in favored locations.   A ridge of high pressure over the West Coast should keep storminess at bay for at least Tuesday and Wednesday, with fog and smog a good possibility in Cache Valley.  But a persistent westerly flow should break down the ridge allowing storms to our north to brush-by northern Utah.

 

Current Conditions:

Considering the lack of significant new snow, you can still find remarkably good conditions on lots of slopes in the Logan area.   The exceptions are wind-crusted areas exposed to last week's northwesterly winds and sun-crusted southerly facing slopes. With mostly supportable snow underneath the soft surface snow, conditions are perfect for all types of backcountry travel.  You'll find the best snow for recreating on sheltered mid and upper elevation slopes.   You can ride anywhere in these conditions, and trail breaking is fairly easy. 

 

Avalanche Conditions:

The couple inches of light snow from last night won't be enough to change the avalanche conditions much.  Avalanches are still unlikely today in the backcountry.  But you might find a freshly formed wind-drift or two in exposed terrain, especially at high elevations.  As snowfall intensifies this afternoon and overnight, the avalanche danger will rise somewhat.  By tomorrow, you might be able to trigger avalanches on some steep wind-drifted slopes, especially if the wind picks up before then. 

The avalanche conditions could get real interesting the next time we are hit by a significant storm.  The potential for a lingering problem with persistent weak layers is serious.   This weekend's light new snow is falling on and effectively preserving weak snow, transformed on the surface during the recent cold, clear weather.  Suspect weak frost crystals or surface hoar platelets are blanketed by an angry inch of light cold powder. I've also found developing weak layers within the existing snowpack.  Buried sugary weak layers  formed or were further weakened by the cold temperatures, especially on slopes with shallow snow-cover.  The shallow snow has rotted out, and I can find very little structure or layering on slopes with less than about 3', where large-grained sugary snow or depth hoar has formed.

Bottom Line:

There's a LOW avalanche danger in the backcountry today.  Avalanches are unlikely, with isolated exceptions on some wind-drifted slopes steeper than about 35 degrees.  The danger of fresh wind-drift avalanches on steep slopes above 8000' facing north through southeast could increase to MODERATE by tomorrow.

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 Monday morning.   I will update again on Tuesday 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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