Avalanche Advisory
Advisory: Logan Area Mountains Issued by Toby Weed for Monday - December 29, 2014 - 7:12am
bottom line

Heightened avalanche conditions exist and there's a MODERATE (level 2) danger in many areas. You still might trigger a dangerous and destructive persistent slab avalanche on a steep upper or mid-elevation slope facing the northern half of the compass. Substantial drifting of light powder yesterday created dangerous wind slab conditions and a CONSIDERABLE (level 3) danger in terrain exposed to wind, mainly at upper elevations.

  • 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.
  • Strictly follow safe travel protocols. Only expose one member of your party at a time, and keep a good eye on each other.




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

The Tony Grove Snotel reports another 8 inches of new snow from yesterday and 69 inches of total snow at the 8400' site containing 138% of average water for the date, and its 7 degrees this morning. The UDOT Hwy 89 Logan Summit weather station is showing light east or down-canyon wind this morning and a chilly 4 degrees. Lots of people are finding very good cold smoke powder conditions and we've received reports of "in your face" and "over the hood" conditions from across the zone. West winds yesterday caused significant drifting of the light density snow, and the winds during periods of rapid accumulations loaded the powder into lee slope terrain. Digging shows there is still potential for dangerous and destructive persistent slab avalanches, but the probability of triggering one continues to gradually diminish.

Still pretty shallow and bushy down low in Wood Camp. (12-27-2014)



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. Looks like he escaped the 2 to 3 foot deep by around 200' wide avalanche, which failed on weak snow that was on the surface during the December dry spell.
  • I was able to easily trigger manageable dry sluffs and crack out some small soft powdery slabs yesterday in the Beaver Backside backcountry.

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

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.


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


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

Yesterday's drifting of the light powder snow certainly increased the potential for fresh wind slab avalanches. Many new drifts will be quite soft and perhaps rather undetectable by feel, but maybe very sensitive. Others in exposed upper elevation terrain will be a bit stiffer and more stubborn. These will appear rounded, perhaps chalky looking, and may be hollow sounding. Increasing east winds today will complicate matters, drifting and cross-loading snow much differently then it was with west winds yesterday. Avoid fresh drifts and wind slabs on the lee side of ridge-lines and in and around terrain features like gullies, scoops, cliff-bands, and sub-ridges.

weather

Snow showers will likely continue today, with little in the way of additional accumulation, and it'll be cold, with 8500' temperatures dropping to around 4 degrees and wind chills of around negative 17. Expect moderate and increasing east winds during the day, which will complicate the drifting patterns of the copious light powdery snow currently on the surface. Clearing tonight will cause mountain temperatures to plummet well below zero, and continued strong east winds will create wind chills pushing -30 degrees! It'll be mostly sunny and cold tomorrow, with high temperatures in the lower single digits, and continuing strong east winds creating wind chills of around negative 32 degrees!

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.