Avalanche: Turnagain

Location: Tincan

Date:
Observer:
Route & General Observations

We toured up the Tincan trees to check out how this awesome storm is affecting the stability. Driving from Seward the precipitation and wind was most intense in Seward, Moose Pass, and Summit Lake. Snow line was around 1,400’ at Summit with a bit of snow on the road. Turnagain Pass was cooler with snow line around 1,000’, snowing at the parking lot, and less wind. The wind was more intense near treeline and was forming fresh wind slabs that produced shooting cracks when we jumped on small steep test slopes. The snow was warm and heavy producing lots of roller balls, but there wasn’t enough new snow in sheltered areas to make any avalanches. The stability was good in our pit location. The skiing was good on the new snow on top of the supportable crust until about 1,400′ when it changed significantly and became really wet and sticky.

Avalanche Details
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Trigger UnknownRemote Trigger Unknown
Avalanche Type GlideAspect Southwest
Elevation 1700ftSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

We observed a new glide avalanche on John Mountain across from Jerome Lake in the Summit Lake zone, it was relatively small, but interesting to see a new glide after very little activity for the past few weeks. We also quite a bit of wet avalanche activity between Moose Pass and the Sterling Wye where the precipitation and wind were more intense.

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?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?Yes
Observer Comments

There was a new glide avalanche on a southwest aspect of John Mountain in the Summit Lake Zone and lots of wet avalanche activity between Moose Pass and Summit Lake. Precipitation rates and wind loading were high enough to create unstable conditions throughout the zones. The visibility in Turnagain Pass was very limited so we couldn’t get a good look for new avalanches there. There was active wind loading from northeast winds during our tour and fresh wind slabs were producing shooting cracks.

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

It was a storm day with very low visibility, high precipitation rates (except Turnagain Pass which was less stormy in general), and strong east wind. The ridgetop winds in Turnagain Pass were strong and transporting snow in the treeline elevation band as well.

Snow surface

It was snowing at the Tincan parking lot and there were a few inches of new heavy snow on top of a melt-freeze crust that formed yesterday as this storm came in warm with rain and then froze. At treeline there were places where the crust was on the surface and places where there were wind drifts from the active wind loading.

Snowpack

We dug a pit at 2,100’ on a south aspect. The snowpack was almost 7’ deep (205cm). We found the January facets about 1.5’ (44cm) below the surface. The layer is about 1’ (35cm) thick, the facets are rounding and 1F in the hardness profile. This is all good news for this location. We did not get any concerning test results (CT23 PC, 14cm down, CT29 PC, 19cm down, and ECTX). We will continue to monitor this layer and still have concerns about it in places where it isn’t as strong and where it might be getting more stress from new snow and wind.

Photos & Video
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