Observation: Turnagain

Location: Tincan Trees

Route & General Observations

We took a walk through Tincan trees to test and observe any obvious signs of wind loading or avalanches. We dug two pits one halfway through the trees and the other at tree-line. Best of all we had some pretty great powder turns on the way down with no alders to manage.

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Observer Comments

There were some signs of wind-loading on isolated terrain features but they did not fail when ski cut.

Weather & Snow Characteristics
Please provide details to help us determine the weather and snowpack during the time this observation took place.

It snowed intermittently throughout the day. We had calm winds and light snow at around 12:30 in the trees. Winds picked up when we got up to tree-line with increased snowfall (S1) although they where not great enough to transport or move any snow.

Snow surface

The first 2" of snow had fallen within the last 12-14 hrs and the next 5" of notably light snow we predicted to be more than 24 hrs old. We did not notice any wind crusts throughout the day but around 1800' on a NW facing aspect we were able to located a small crust about 2-3" below the snow surface. This crust felt more like a melt freeze layer and was brittle and less than 1 cm thick.


Pit 1: Was dug at 1524' on a west facing slope, here the snow was about 96" deep. 8" below the snow surface we found a layer of buried surface hoar that failed but did not propagate in our stability tests (CT12, ECTN18). Around 13" deep we found another weak interface that also failed but did not propagate (CT21 sudden planar, ECTN27). It was difficult to tell whether this layer had any BSH but it was obvious that there was some inconsistency in the snowpack layering. Around 30" below the snow surface we found the 1/25 melt freeze crust and 50" deep we found the 1/10 buried surface hoar.

Pit 2: We stopped at tree-line due to poor visibility and dug a pit at 2150' on a west slope. The snowpack was shallow here, only 65" deep which we attribute to its exposure to wind scour. About 9" deep we found a layer of buried surface hoar but the crystals were small (3mm) and hard to identify. In our stability test this layer failed in one test (CT17, ECTX). We also had a failure 15" down at a storm snow interface (CT20). 2' deep we found the 1/10 buried surface hoar. The holiday crust was 2.6' deep.

Ultimately the snowpack gave us some hints of reactivity but no propagation in any layers. What was the most surprising was the sudden plainer results in our CT test below tree-line. These tests indicated some signs of instability leaving us uncertain with the overall snowpack stability. Additionally, we were unable to make any conclusions regarding the distribution of windslabs at higher elevations.