Observation Date
12/18/2014
Observer Name
Greg Gagne
Region
Salt Lake » Big Cottonwood Canyon » Silver Fork
Location Name or Route
Silver Fork
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Speed
Calm
Weather Comments
Snowed most of the morning with occasional bursts of S1 or S2 snowfall (1-2 cm/hr). Winds were calm. Temps -4 C.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments

What a treat. The upper reaches of Silver Fork had accumulated up to 10 cms (4") new snow when we were exiting at 1230.

Avalanche Problem #1
Problem
Wet Snow
Problem #1 Comments

Fairly easy to get the top 10-30 cms of snow to sluff on steep slopes. Given our current snowpack structure, this is the only avalanche problem I can currently identify. However, weak layers in these top 10-30 cms may become an issue once we get a slab on top.

Snow Profile
Comments

Route today was Silver Fork from Solitude. Travel was West Bowl - Hideaway Park - Quick Silver. Snow profile is composite view of snowpack structure on northerly aspects > 9000'.

Am trying to get a handle on the current state of our snowpack so to make good decisions if/when it does snow. LOTS of quick hand pits and inverted pole probes to gauge the depth and weak layers of the snowpack in this area. These are my general thoughts of the upper reaches of Silver Fork:

- Snowpack is deeper than I expected with typical depths of 60-75 cms (24-30") with some areas approaching 90 cms (36")

- Weakest snow is found in the top 10 - 30 cms consisting of recent storm snow and decomposing fragments and near-surface facets. Surface sluffs were moving, but they required fairly steep slopes.

- Fair amount of spatial variability with some temperature crusts and 1F/P hard wind slabs down about 30 cms in some areas.

- A midpack 1F slab on top of 10 cms of rounding facets and depth hoar. In deeper snowpack areas, I do not think these basal weaknesses will become an issue with an increase in load.

Where I was traveling today, I came away with the general feeling the snowpack does not seem overly weak, but weak snow near the snow surface will be worth watching with any increase in load.

Without a slab on top, the snowpack is currently stable but has persistent weaknesses in the top ~30 cms of snow. Expected snowfall over the weekend with rising snow densities ("upside-down" as Evelyn described this morning) and modest water weights may be enough to make these weaknesses become active.

Rather good ski and travel conditions with a supportable slab and a surprising refresh of snow in the morning.

Fingers crossed for an extended stormy period over the next 7-10 days. (Well, really should say next 70 - 100 days.)

Am calling the hazard mostly Low, but with sluffing in the snow surface, a Moderate hazard on steeper northerly aspects. However this is a very easily managed avalanche problem.

Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Moderate