Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Tuesday - December 30, 2014 - 7:26am
bottom line

Strong east and down canyon winds created dangerous avalanche conditions in the backcountry. There's a CONSIDERABLE (level 3) danger. Natural wind slab avalanches are possible and triggered avalanches are likely in drifted terrain at all elevations and on slopes facing every direction. Also, you still might trigger a deeper, dangerous, and destructive persistent slab avalanche on a steep upper or mid-elevation slope facing the northern half of the compass.

  • Careful snowpack evaluation, cautious route finding, and conservative decision-making will be essential for safe backcountry travel.
  • Avoid fresh drifts and wind deposited snow on steep slopes at all elevations.
  • Strictly follow safe travel protocols. Only expose one member of your party at a time, and keep a good eye on each other.




avalanche warning

THIS AVALANCHE WARNING IS FOR CANYON MOUTHS AND FOOTHILLS OF CACHE...DAVIS...WEBER AND EASTERN SALT LAKE COUNTIES. STRONG WIND WILL CREATE POTENTIALLY DANGEROUS WIND SLAB AVALANCHE CONDITIONS IN LOW ELEVATION AREAS WHERE PEOPLE DO NOT NORMALLY SEE AVALANCHES. AVALANCHE DANGER IS EXPECTED TO INCREASE TODAY AND CONTINUE INTO WEDNESDAY.

special announcement

We will offer an Avalanche Awareness Class, for beginners and as a refresher for those already with some training, including a Field Day in the backcountry. Class begins on January 8 (evening) and all day Saturday January 10. Call Paige at 435-757-2794 for more information.

current conditions

As we used to say in New Hampshire, "it's wicked weather out there!" The Tony Grove Snotel reports 66 inches of total snow at the 8400' site containing 136% of average water for the date, and its -9 degrees this morning. The UDOT Hwy 89 Logan Summit weather station is showing southeast or down-canyon wind, gusting into the 30 mph range this morning and a chilly -5 degrees. Strong east winds overnight changed the landscape and drifted snow into strange and perhaps unexpected areas, especially at lower elevations and near canyon mouths.



recent activity
  • A fairly widespread natural avalanche cycle occurred around a week ago at upper and mid-elevations in the Logan Zone with the moist Solstice Storm.
  • A rider triggered a good sized persistent slab avalanche Tuesday in the Rodeo Grounds on the east side of Logan Peak. The 2 to 3 foot deep by around 200' wide avalanche looks to have failed on weak surface snow buried by the Solstice storm.
  • Observers report a 1' deep and 50' wide wind slab avalanche from Sunday in the Tony Grove Area.
  • Back country skiers triggered a large and dangerous persistent slab avalanche In Big Cottonwood Canyon yesterday. The 3' deep avalanche failed on weak snow that was on the surface during the December dry spell. Report.... HERE

Visit our Backcountry Observations Page for more information.....


Avalanche Problem 1
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

The ongoing east wind event built wind slabs in strange and unexpected areas overnight. Of special concern will be lower elevation slopes in the foothills and near canyon mouths, but wind slabs likely built at all elevations and on slopes facing every direction. Wind slabs form in deposition areas on the lee side of ridge-lines and in and around terrain features like gullies, scoops, cliff-bands, and sub-ridges. These will appear rounded, perhaps chalky looking, and may be hollow sounding. Avoid fresh wind drifts and wind slabs on all slopes steeper than about 30 degrees.

Avalanche Problem 2
type aspect/elevation characteristics
LIKELIHOOD
LIKELY
UNLIKELY
SIZE
LARGE
SMALL
TREND
INCREASING DANGER
SAME
DECREASING DANGER
over the next 24 hours
description

We're now in a tricky "Low Probability, High Consequence" situation. During the Solstice Storm, heavy wind-blown snow overloaded a weak layer consisting of faceted snow and surface hoar that was on the snow surface before the storm arrived. Dangerous and destructive triggered avalanches remain possible in some terrain steeper than about 30 degrees. The danger will be most pronounced on drifted slopes facing the northern half of the compass. Audible collapsing or whoompfing noises indicate dangerous persistent slab avalanche potential, and in some areas you still might trigger a dangerous avalanche remotely, from a distance, or worse from below.


****Video observation (snowpit) from Bobcat in the Wood Camp Area (12-27-2014)............HERE


weather

It'll be sunny and wicked cold in the mountains today, with 8500' temperatures around -3 degrees and very strong east winds. This combination will create wind chills around 36 degrees below zero, which is dangerously cold obviously. Expect below zero temperatures again tonight with continuing fairly strong east northeast wind. Wednesday will be mostly sunny, with 8500' high temperatures around 15 and gradually diminishing northeast winds.

Check out our one-stop weather page........HERE

general announcements

You can now receive advisories by email for each region in the state including Logan.  Go here for details.

 Get your advisory on your iPhone along with great navigation and rescue tools.......  Utah Avalanche Center mobile app 

Please submit snow and avalanche observations from your ventures in the backcountry HERE. You can call us at 801-524-5304 or email HERE, or include #utavy in your Instagram or Tweet us @UAClogan. To report avalanche activity in the Logan Area or to contact the local avalanche forecaster call me, Toby, at 435-757-7578. 

I'll regularly update this advisory on Monday, Wednesday, Friday, and Saturday mornings by about 7:30.   This advisory is produced by the U.S.D.A. Forest Service, which is solely responsible for its content. It describes only general avalanche conditions and local variations always exist.