Observation: Turnagain

Location: Silvertip

Date:
Observer:
Route & General Observations

Ascended N ridge of Silvertip to about 3000′ via Silvertip Creek drainage. No obvious signs were observed within this drainage. There was recent wind slab avalanches one ridge over on a NE aspect (observed yesterday from Johnson Pass trail head.) Old debris was observed in many steep and/or channeled terrain features,¬†all from past storm cycles.

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

Small localized cracking under foot, no shooting cracks in 4" wind slabs between 2500-3000' along the N Silvertip Ridge.

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

Sunny with thin cloud cover
5F - 0F
Winds were calm until and ~3pm and could feel light East breeze
No recent precip

Snow surface

8" of loose settled snow is sitting on a firm melt/freeze crust to about 1600'
Light wind skin until ~2000' transitioning into stiffer 2-4" thick hard slab/sastrugi above.

Snowpack

Dug a pit at 2500' on 25 degree slope on a NNE aspect along Silver tip ridge in a wind loaded area that was supportable and hallow sounding. The height of snow 275cm and average depth in this area was 180cm. Our pit was only 90cm deep, we did not dig to the ground. We found a 4" hard wind slab that failed on isolation in Compression Test and propagated with only 4 taps in Extended Column Test. The snow was 4F hard just below this layer. We found the Feb.9 buried surface hoar layer 65cm below the surface which failed in Compression test with strong force (CT25) and did not fail in ECT. The buried surface hoar was between 3-5mm in size and was not standing up in pit. It was sandwiched between two pencil hard layers.

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.