Observation: Alta Periphery 1/1/2012

Observer Name:

Greg Gagne

Observation Date:

01/01/2012

Region:

Salt Lake
Little Cottonwood Canyon
Alta Periphery

Location or Route:

Alta Periphery

Weather

Sky:

Clear

Weather Comments:

Windless, mild, bluebird. Tiresome.

Snow Characteristics

Snow Surface Conditions:

Faceted Loose

Wind Crust

Melt-Freeze Crust

Snow Characteristic Comments:

About every kind of imaginable snow condition except for soft powder. Noted a faint dirt layer in some places - presumably from strong westerly winds Friday night. Rain crust (~2 mm) was very spotty and quite variable. In some areas where the wind had eroded the surface, the crust shown brightly and was quite apparent. The view somewhat reminded me of the snow surface following the infamous MLK 2011 rain crust event.

Red Flags

Cracking

Collapsing

Red Flag Comments:

Several collapses and cracking in the top 5-10 cm (2-4") of snow. Our weak snowpack is clearly cranky.

Primary Concern

Primary Concern:

Wind Slabs

Probability:

Moderate

Elevation:

High

Mid

Trend:

Same

Primary Concern Comments:

Was finding several wind slabs, even some on SW aspects despite the winds from the strong wind event early this weekend were primarily westerly. Most of these slabs were shallow (5-15cm/2-6"), but they were pencil hard and sitting on top of very weak snow. The included photo highlights travel conditions - the wind slabs are so hard they are supportable even though they aren't very thick. Yet you hit a thinner spot and go crashing down through the super-weak snow to the rocks below.

snow_profile_location:

Comments - Photos - Videos (group 1)

Hazard is probably Considerable where there is a recent wind slab. Much of the terrain has a Moderate hazard, bit given the varied distribution of these wind slabs, it is very easy to quickly go from an area of Moderate hazard where there is no wind loaded snow to an area with a hard wind slab and much trickier avalanche conditions.