Avalanche: Turnagain

Location: Tincan Common

Date:

March 29, 2016 8:00pm

Observer:

A. Johnston-Bloom Professional

Route & General Observations

Road observations to Johnson Pass trail head and standard Tincan up-track to 3200′. Warm air temperatures creating damp snow to the ridge.

Avalanche Details

If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.

Trigger	Natural	Remote Trigger	0
Avalanche Type	Unknown	Aspect	Unknown
Elevation	unknown	Slope Angle	unknown
Crown Depth	unknown	Width	unknown
Vertical Run	unknown

Avalanche Details

Watched a glide avalanche in motion above Bertha Creek campground. This ran over glide debris from a large release last week.

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

Easy to trigger loose avalanches from skis or board at 2000'. Large skier triggered roller balls at 3200'.

Weather & Snow Characteristics

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

Weather

Mostly overcast with periods of sunshine
Calm winds
Warm temperatures. 38F in the shade @ 3000'. 45 @ 1000'
No precipitation

Snow surface

1000-1800' 2-6" wet snow over melt-freeze crust
1800-2500' 5-8" of damp snow with 1 inch of wet snow at surface over a melt-freeze crust
2500-3200' 6-12" of damp snow with 1-2 cm of wet snow at surface over a melt freeze crust

Snowpack

Dug @ 3000' on a West aspect, 25 degree slope. Pit depth 100 cm. Melt freeze crust 25 cm below surface and 45 cm below surface. The snow from the 3.19 storm is preserved above the lower crust. ECT P 24 and CT 20 x 2 on this layer. The new snow was reactive in shovel tilt tests and hand shears. There is also a drier layer of snow above the upper melt freeze crust. The top 10 cm of snow is stiffer due to wind effect and there was 1 cm of wet snow at the surface. (See photo)

Hand pits along the skin track showed mixed results with how well the new snow has bonded to the old crust. It sheared easily in some spots and seemed completely stuck on in others. Tests slopes at 2000' were easily triggered on the crust.

Photos & Video

Please upload photos below. Maximum of 5 megabytes per image. Click here for help on resizing images. If you are having trouble uploading please email images separately to staff.