|Location:||Tincan up to 2,500'|
Route & General Observations
Common skin track to the top of the Tincan Trees and up a bit more to 2,500′. It was a storm day on Turnagain Pass.
|Trigger||Skier||Avalanche Type||Soft Slab||Aspect||Southeast|
|Elevation||2500ft||Slope Angle||unknown||Crown Depth||8in|
Skier triggered avalanche on the SE facing slope opposite the 'tincan trees'. Triggered from the broad ridge by pushing snow on a steep small rollover. This shallow slab ran 150-200' to the depression/gully below then (we think) sympathetically triggered 3 more pockets on the other side of the gully. These pockets were small - 30' wide and 8-10" deep.
Weak layer was the early December facets.
VERY TOUCHY above treeline !
Obvious signs of instability
|Recent Avalanches?||Yes||Collapsing (Whumphing)?||Yes||Cracking (Shooting cracks)?||Yes|
All the signs were present for an unstable snowpack above the trees.
Snowing around .5-1" an hour
Winds light in the trees but moderate just above treeline from the North
Temps warm, 30F at at the parking lot and upper-20'sF at 2,500'
3-5" and counting of new snow! This was moist and dense at 1,000' but became lighter and low density at 2,000'. Winds have been moving the snow around above the trees, with such low visibility it was hard to tell how much wind effect was occurring in the Alpine.
Alpine elevations: Unstable. 6-10" slab over weak facets on Tincan. Slab is composed of the new snow + 3-4" of settled snow from Dec 15/16. Facets are from the Dec 1-Dec 14 clear period. This faceted layer is definitely proving to be dangerous. It was exceptionally easy to trigger the above avalanches.
In the Tincan Trees: Loose new snow over loose faceted snow = lots of sluffing and in some areas just enough settlement occurred in the new snow to form shallow 'storm slabs' that propagated 30-50'.