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Observation: Mirror Lake Highway

Observation Date
3/13/2013
Observer Name
jg
Region
Uintas
Location Name or Route
Mirror Lake Higway - Pass Lake Area
Weather
Sky
Few
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Blue skies early in the day, scattered thin clouds later in the day. Wind light at 10,000 ft. early in the day blowing from the NW shifting around noon and blowing from the WNW at more moderate speed with strong gusts on the high ridges at 11,000+ft.
Snow Characteristics
Snow Surface Conditions
Dense Loose
Wind Crust
Melt-Freeze Crust
Damp
Snow Characteristics Comments

Variable snow surfaces encountered during the day. Melt-freeze crusts on solar aspects, wind-jack in exposed terrain, settled, dry, dense snow on sheltered north facing slopes, damp snow on all aspects below about 10,500 ft.

Red Flags
Red Flags
Recent Avalanches
Rapid Warming
Poor Snowpack Structure
Red Flags Comments
The winds helped keep the snow suface a little cooler than if they hadn't been blowing. South faces were wet but not sloppy at elevations above 10,000ft. I saw one recent (probably from 3/12) wet slide on a steep south facing slope at about 11,000ft. I didn't get a great look but, by the looks of the dirty debris, it seemed to have gone to the ground.
Avalanche Problem #1
Problem
Wet Snow
Trend
Increasing Danger
Problem #1 Comments

With warm temps and light refreezes overnight south facing slopes should be approached with caution. South facing slopes have poor structure and pit test results show propensity for shear propagation. Trend for the next few days should be increasing based on forecasted temps.

Avalanche Problem #2
Problem
New Snow
Trend
Same
Problem #2 Comments

Pit test results on both north and south facing slopes reflected a propensity to shear. Same to decreasing danger.

Comments

Traveled from 10,000-11,000+ft, all aspects, slope angles to 38 degrees. A lot of recent wind in the alpine terrain has left a lot of the upper elevation slopes pretty wind-jacked. Sheltered north facing terrain was still holding dense, creamy, soft snow. Snow was damp on all aspects. North facing slopes were dry above 10,500ft.

Pit on NW facing slope about 10,500ft. HS 61in. (154cm). CT18Q2 on needles about 11 in. (27cm) down in the pack. ECT38 SDN Q2 on small grained facets about 19in. (47cm) down in the pack. It took some force but fracture propagated across column in my ECT test.

Pit on a SW facing slope at 10,300 ft. HS 48"(123 cm). CT12Q2 on large grain facets about 19" (47 cm) down in the pack. ECT12SPQ1 - failed in the same place as CT. Very weak structure with little effort to propagate a fracture. The top 19" are a combination of melt-freeze crust/facet sandwiches sitting on large grain rounding facets to the ground.