Observation: Turnagain

Location: Tincan

Route & General Observations

Standard route to 2300′.

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)?No
Observer Comments

A few very small slab avalanches, both natural and skier triggered, in the Tincan Trees. Most small test slopes were not reactive.
We thought we heard a natural run, possibly on the front side of Seattle Ridge, at 14:45.
No shooting cracks but some localized cracking down to the new/old interface on steep rolls, was more slabby below 1200'.

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

Snow fall throughout the day. It was initially lighter then began snowing 1"/hr around noon. 5" of new snow between 10:00-15:30. Lots of rimed snow flakes and riming of surfaces.
On the drive up rain/snowline was around 400'. On the drive down it was almost to sea level turning to rain at the Ingram corner.
Temperatures in the low 30°Fs to mid 20°Fs
Gusty NE winds above 2000', active wind transport

Snow surface

Soft new snow
Noticeably heavier with more water content on the decent around 1600' and below.
Wind drifting and surface stiffening in wind exposed terrain. Ski pen decreased from close to 2' to 4-5" in the wind affected terrain.


1.5-2' of storm snow over buried surface hoar and small near surface facets at the new snow/old snow interface.

We dug at 1700' on SW aspect, 28° slope, HS: 165 cm, buried surface hoar was 65 cm down, CT 25, CT 23, ECTP 27. Buried surface hoar was small 2-4 mm and mixed in with near surface facets. However, the layer was distinct in the snow pit wall. We did not dig down to the 12.1 crust layer down 145 cm.

We dug at 2200' on W aspect, 22° slope, HS: 290 cm, buried surface hoar was down 65 cm again. 2-3 mm and laid over. CT 23, CT 27, ECTN 25. The 12.1 crust was down 185 cm. We did not dig to this layer.

On the way down we quickly dug in at 1100' on W aspect and found the buried surface hoar down 60 cm and the grains were 8-10 mm and still standing intact in the pit wall. CT 13, CT 12.

In the pits we dug the slab was still soft. It is likely more reactive in the Alpine where the slab is stiffer and the loading more intense. There is the potential that as the soft snow settles and becomes more cohesive in protected terrain it may be more reactive. This is a question for the days to come. We also are curious about what the new/old interface looks like at higher elevations. How widespread is the the buried surface hoar layer? Did it form on hard surfaces? Is the interface without the buried surface hoar faceted enough to be an issue?

Photos & Video
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