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

Saturday, December 31, 2005

Hello, this is Toby Weed of the Forest Service Utah Avalanche Center in Logan.  It's Saturday December 31st at 7:15 am.  This advisory is brought to you in part by the Friends of the Utah Avalanche Center in Logan with help from Backcountry Access, manufacturer and distributor of avalanche safety, ski touring, and winter hydration products.

Mountain Weather:

The National Weather Service in Salt Lake has issued a Winter Storm Warning for all the mountains of northern Utah through noon on Sunday.  Heavy, wet snow and very high winds are expected at high elevations, with the rain-snow line rising up to around 8500' today.  The cold front is expected late tonight and lower elevation rain will turn back to snowfall, with the snow-line dropping down to about 6000'.  Snowfall and winds will taper off tomorrow morning, but an even more potent storm will cap things off on Monday into Tuesday.

Once again, snow totals are impressive in the Logan Area Mountains.  As of 5:00 am, the 8400' Snotel site at Tony Grove reports about 14" of snow containing 2.2 inches of water in the last 24 hours.  Meanwhile, at the Campbell Scientific weather station at 9500' atop Logan Peak, southwesterly winds are howling, with overnight hourly averages approaching 40 mph.  Temperatures are hovering at 25 degrees on Logan Peak and 31 at Tony Grove.

Avalanche Conditions:

 Deep wind-drifts and heavy inverted snow up high, as well as rain and perhaps unpleasantly soggy conditions below about 8000' will probably keep most of you out of active upper elevation avalanche terrain today.  If the weather and snow conditions aren't enough to keep you off steep slopes in the backcountry, it's likely dangerous avalanche conditions will.  Overnight, heavy snowfall and high winds drifted tons of snow into steep lee slopes and avalanche starting zones across the region.  Today, significant natural avalanches are possible on some upper elevation wind-loaded slopes.  More importantly, human triggered avalanches are also possible on many other slopes steeper than about 35 degrees in the backcountry.  You might trigger avalanches on any steep slope with significant buildups of upside-down or inverted new snow, even on normally sheltered slopes.  At 8400', we've already picked up well over 6 inches of water since Christmas.  With this amount of new weight on the snowpack, buried weak layers could start to get active. Dangerous hard-slab avalanches involving old snow are becoming increasingly possible. Wet avalanches are possible on steep lower and mid-elevation slopes with new snow that get saturated today by rain and warmth.

If you do head into the backcountry, watch for sure signs of instability like cracking, spooky noises, or nearby natural avalanches.  You'll need to be on top of your game.  You should stick to lower angled terrain, and stay out from underneath steep slopes and obvious or potential avalanche paths.  Follow strict avalanche safety protocols, like only exposing one person at a time and keeping a good distance between you while a close eye on each other.

Bottom Line:

Today, there's a CONSIDERABLE avalanche danger on steep upper elevation slopes in the backcountry.  Human triggered avalanches are possible on numerous slopes steeper than about 35 degrees, and some natural avalanches could occur.  Rainfall and warmth may also cause a MODERATE danger of wet avalanches on steep lower and mid-elevation slopes with saturated surface snow. With continued heavy snowfall and very strong winds, the danger could to rise to HIGH on some upper elevation slopes overnight. 

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.

   I will update this advisory Sunday morning by about 7:00 am.

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. 

National Weather Service - Salt Lake City - Snow.