Observation: Turnagain

Location: Sunburst

Date:
Observer:
Route & General Observations

Normal Sunburst uptrack to ~3400′

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Obvious signs of instability
Recent Avalanches?No
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?No
Observer Comments

At 2200' we stepped off the main skintrack to look at the snowpack structure and triggered a collapse. The new storm snow had a kind of hollow feeling when breaking trail and was more consolidated and slabby than what I saw on Wednesday on Tincan.

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

Temps in single digits, calm winds, no precip. Clouds were broken early in the day then cloud levels dropped in the afternoon and became a a more consistent layer.

Snow surface

Settled powder. The new snow from this week was still very soft and trail breaking was deep, but it was notably more cohesive and slabby compared to Wednesday on Tincan.

Snowpack

We dug two snowpits along the uptrack (2200', 3200') and got information from Andrew about a third (3500') at a higher elevation. All three pits showed poor structure, with multiple weak layers underneath 50-60cm of new snow from this week. Only one of our extended column tests showed propagation, which was the upper pit at 3500' (See photos). This pit had a layer of firmer snow above the weak layer which was likely caused by wind transport early this week.

We were surpised not to see propagation in either of the lower pits because of all the weak layers present. This can be one of the tricky things about digging pits. You get mixed results that don't always line up with your expectations. It is important to remember that a snowpit is just a single measurement from one location and the results of stability tests can change dramatically if you move just a few feet across or up slope. My take away from these pits are that, despite the mixed results in our stability tests, we have widespread weak layers in the snowpack which could produce large avalanches with the right combination of slab and weak layer characteristics.

Photos & Video
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