Observation: 10420

Observation Date
1/23/2016
Observer Name
Greg Gagne with Westminster Level 1 Class
Region
Salt Lake » Big Cottonwood Canyon » 10420
Location Name or Route
Peak 10420'
Weather
Sky
Obscured
Precipitation
Moderate Snowfall
Wind Direction
Southwest
Wind Speed
Strong
Weather Comments
Calm in the am ahead of the storm with strong gusts on West ridge of Peak 10420' from the S/SW. Periods of S2 snowfall late afternoon.
Snow Characteristics
New Snow Depth
2"
New Snow Density
Medium
Snow Surface Conditions
Powder
Faceted Loose
Wind Crust
Damp
Snow Characteristics Comments

Perhaps 5 cms new exiting at 4 pm. Varied snow surface with some near surface facets noted on protected, northerly aspects. Snowpack was 135 cms on northerly aspect at 10000'.

Red Flags
Red Flags
Wind Loading
Red Flags Comments
Pre-frontal winds seemed the biggest red flag today.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments

Our group today felt the weaknesses in the top 50 cms of the snowpack were the biggest concern. With no propagations with ECTs, we did not feel the current slab was enough to overload the weaknesses, but were concerned with new wind loading and snowfall.

Comments

Solid group from Westminster College Level 1 today. Travel was along west ridge of Peak 10420. Here is the summary of what our group found:

- Three distinct weaknesses in the top 50-60 cms (20-24") of the snowpack. Very easy to isolate the weakness with shovel tilt as we were getting clean, resistant-planar shears.

- Extended column tests were getting collapses of the weak layers, but no propagation of the slab.

- Snowpack felt "rightside up" as it progressed from F-hard snow at the surface to 1F snow just above the facets at the ground. The faceted layer at the ground ranged from F to 4F hard.

- Traveling into terrain with wind loading we were finding very shallow, sensitive wind drifts by mid-day on aspects being loaded from the W/SW winds.

Overall we felt the hazard was Moderate in mid-elevations, and Considerable in upper elevations with wind loading.

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