Avalanche: Turnagain

Location: Tincan

Route & General Observations

We remotely triggered a fairly large avalanche on the south side of Tincan today near the Snake Pit. The avalanche failed 2′ deep on the layer of buried surface hoar that has been giving us so many problems for the past week. It was around 75 feet wide and ran about 150 vertical feet. The funny thing is, we triggered this avalanche while we were digging pits to test that weak layer on a flat bench just above the slope that slid. Solid evidence that the layer is still a concern for now.

Avalanche Details
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Trigger SkierRemote Trigger Yes
Avalanche Type Soft SlabAspect South Southwest
Elevation 2000ftSlope Angle 35deg
Crown Depth24ftWidth 70ft
Vertical Run 150ft  
Avalanche Details

We dug two pits on a low-angle south-facing bench at 2100', right by the Snake Pit. We wanted to check the 1/10 surface hoar layer, and got propagating (unstable) results in both pits (ECTP25 both times). This ended up being of secondary importance since we triggered an avalanche remotely while we were digging! The avalanche failed about 50' below our pits where the slope rolled over to 35-40 degrees.

Red Flags
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Observer Comments

No warning signs prior to triggering the avalanche. It is worth noting that this layer was really hard to find with hand pits along the skin track on our way up. It is just getting deep enough that typical tests for shallower problems are becoming less reliable. This includes the common warning signs like shooting cracks and collapsing.

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

Weather: Rain up to around 800' on the drive up, snowing just a little under an inch an hour while we were out. There was about 3" new snow on the truck when we got back to the parking lot after being out for around 4 hours. Winds were light out of the east, with fully cloudy skies all day.

Snow surface

There was a little over a foot of soft snow on the surface, and it seemed like maybe 2-3" was from this morning before we got out there. There was a paper thin crust under about 2" dry snow up to maybe 1300'.


**See attached photos for more detailed pit info**

Key points:

- The BSH layer was about 2' deep on average, showing poor stability in our tests in two different pits. These pit results were validated by the fact that we triggered a big avalanche on that layer while we were digging.
- The Christmas crust was about 4' deep in our pits, and was around 6" thick. It is still locked up, with strong snow above and below. It is something we will be tracking in the weeks to come, just to make sure it doesn't start developing facets within, above, or below the crust. For now it is adding strength to the snowpack.

Photos & Video
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