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Taos Avalanche Center

Professional Observation

Basic Information

Observation Details

Observation Date:
December 4, 2020
Submitted:
December 5, 2020
Observer:
TAC - Andy Bond
Zone or Region:
Taos Area
Location:
Long Canyon

Signs of Unstable Snow

Recent Avalanches? 
None Observed
Cracking? 
None Experienced
Collapsing? 
None Experienced
We did get one collapse with shooting cracks on an obvious wind-loaded pocket on the ridgeline.

Bottom Line

It's a safe assumption to assume that if you are skiing on a West aspect above treeline right now, you will be skiing on some form of a slab. These slabs are stubborn and we couldn't get any to release. The question is what weak layer is beneath and what are the consequences below. These slabs are pocketed but may step down into weak faceted snow further down the track.

Media

Just below ridgeline on a West aspect.  These slabs are stubborn and not evenly distributed across slopes.
Moderate E winds transporting snow onto West Aspects Above Treeline

Advanced Information

Weather Summary

Cloud Cover:
Clear
Temperature:
22 - 33
Wind:
Light , NE

A beautiful sunny day with light winds below treeline and moderate sustained winds at ridgetops out of the ENE. We did see plumes of snow drifting off of ridgelines in the higher mountains. Temperatures got above freezing below 10,000'

Snowpack Observations

Went to check out Long Canyon for the first time this year. There is not much snow below 10,000' (only a couple of inches) and travel on skis is probably not recommended for this trailhead for the first 800 vertical feet. The track up Long Canyon has close to 30 blowdowns presumably from the 11/8 100 mph wind event.

The shallow East facing slopes from the last three days of moderate ENE winds has stripped much of the East facing slopes to just shallow facets. We dug a pit on an east-facing slope near treeline and found a deteriorating crust with basal facets beneath and decomposing snow above. Not a problem now but will be once we introduce a load and a cohesive slab on top.

Skinning up on steep shady north aspects to the ridgeline was like hiking in scree with 1 step forward and 2 steps back. A pretty good indication these north and shady slopes are faceting all the way to the ground.

We checked out West aspects that ran back into the Colombine Drainage. Just below ridgetops we found stiffer slabs from the ENE winds over the last several days. Just 100' down the path we found less stiff slabs and not as thick. One of the deeper slabs we found was over 2' feet thick and 1 F hard. Our extended column test failed on isolation which sounds scary and is, but we are finding a high level of variability with the underlying stratigraphy.

It's a safe assumption to assume that if you are skiing on a west aspect above treeline right now, you will be skiing on some form of a slab. These slabs are stubborn and we couldn't get any to release. The question is what weak layer is beneath and what are the consequences below. These slabs are pocketed but may step down into weak faceted snow.

Avalanche Problems

Problem Location Distribution Sensitivity Size Comments
Wind Slab
Isolated
Specific
Widespread
Unreactive
Stubborn
Reactive
Touchy
D1
D1.5
D2
D2.5
D3
D3.5
D4
D4.5
D5

Terrain Use

Not sure I would drop a west-facing line right now without thinking about the consequences of popping a stubborn slab right now and what that ride would entail. Good powder skiing in the trees near treeline, just think light thoughts!

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