Logan Avalanche Advisory

Forecaster: Toby Weed

SPECIAL ANNOUNCEMENT

Come support the Friends of the Utah Avalanche Center in Logan next Thursday December 16th at 7:30 pm at the Logan Arthouse and Cinema. We'll be showing KGB's newest film "Wyoming Triumph.' Admission is $10 and tickets can be pre-purchased at http://utahavalanchecenter.org/wyoming_triumph/120611. We'll have a raffle of great gear to support the Friends, so come and get some relief from Finals and enjoy the show! Call 757-2794 for more info.

The Friends of the Utah Avalanche Center in Logan is offering a Backcountry 101 class next weekend... The class starts with a classroom session on Friday evening, and includes a field day in the backcountry on Saturday. click HERE for more details....


BOTTOM LINE

Danger by aspect and elevation on slopes approaching 35° or steeper.
(click HERE for tomorrow's danger rating)


Danger Rose Tutorial

There is a Level 1 or Low danger in the backcountry around Logan, and avalanches are generally unlikely. However exceptions still exist, and wind slab avalanches are possible on some isolated steep drifted slopes, mainly at upper elevations. Generally manageable triggered loose dry sluffs are also likely in steep terrain.. Generally safe avalanche conditions exist in most areas, but you should watch out for loose sugary snow on very steep slopes and unstable stiff wind slabs in exposed upper elevation terrain... It's best to avoid steep slopes with rocks, trees, or other potential terrain traps below that you could be swept into by even a small avalanche....


CURRENT CONDITIONS

The Tony Grove Snotel at 8400' reports 25 degrees this morning, and there is 30 inches of total snow on the ground.. With 6.8 inches of water equivalent, the station sits at 81% of average for the date.. It's 30 degrees at the 9700' CSI Logan Peak weather station, and there is a fairly light northeast wind. The station recorded overnight hourly average windspeeds of a bit less than 20 mph from the northwest.

You'll find pretty good, fast, Colorado-like sugar snow conditions in many areas. But, you have to keep your speed down because you sink pretty deeply into the recrystallized snow, and it's getting easier and easier to hit buried rocks, stumps, or down trees....


RECENT ACTIVITY

No new avalanches reported recently in the mountains of Northern Utah.

We continue monitoring the gradually deteriorating shallow snowpack as high pressure conditions and cold air temperatures are causing it to weaken significantly. The shallow snow is subjected to an extreme temperature gradient when the air temperature is cold, and clear skies allow for significant longwave radiational loss. A temperature gradient drives sublimation of water vapor through the snowpack, which transforms the snow crystals into weak sugary non-cohesive grains called facets. Meanwhile, water vapor near the snow surface freezes and becomes frost or feathery surface hoar. The bottom line is; given the existence of all this extremely weak snow, we'll see a widespread and serious persistent avalanche problem when a slab is built by accumulating snow, especially with the next significant dump.


THREAT #1

WHERE PROBABILITY SIZE TREND
      Over the next 12 hours.

Most of the several-day-old wind slabs are limp or very stubborn, and the danger will be limited only to very steep slopes. Watch out for stiff wind slabs in exposed very steep terrain. Avoid rounded, chalky looking, or hollow sounding drifts on steep slopes near ridgelines and in and around terrain features.. Generally manageable loose dry sluffs involving weak surface snow are likely on steep slopes today, so avoid terrain where you could be swept into rocks or trees below.. Obviously, the consequence of being caught in an early season avalanche is greatly increased by the shallowly buried and exposed rocks you could be raked over...


MOUNTAIN WEATHER

Expect another sunny and fair day in the mountains today, with calm winds becoming a southerly breeze and high temperatures a few degrees warmer than yesterday, reaching a high of around 32 degrees at 8000'. A cold front moving through southern California will push the high pressure off to the east on Monday and bring a good chance of snowfall to the Southern and Central Utah mountains Monday night and Tuesday. This probably won't be enough to scour the stale air out of the northern valleys, but another front will push into our area on a northwesterly flow around late Wednesday. A trough of low pressure will set up over the region allowing the storm track to hit us.... At this point it looks like we get a good chance for accumulating snow in the later half of next week....


GENERAL ANNOUNCEMENTS

You have the opportunity to participate in the creation of our own community avalanche advisory by submitting avalanche and snow observations. You can also call us at 435-757-7578 or 801-524-5304 or email by clicking HERE

Donate to your favorite non-profit – The Friends of the Utah Avalanche Center. The UAC depends on contributions from users like you to support our work.

I will update this advisory by around 7:30 in the morning on Mondays, Wednesdays, Fridays, and Saturdays.....

This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.


This information does not apply to developed ski areas or highways where avalanche control is normally done.  This advisory is from the U.S.D.A. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.


This advisory provided by the USDA Forest Service, in partnership with:

The Friends of the Utah Avalanche Center, Utah Division of State Parks and Recreation, Utah Division of Emergency Management, Salt Lake County, Salt Lake Unified Fire Authority and the friends of the La Sal Avalanche Center. See our Sponsors Page for a complete list.