Avalanche: Hatcher Pass

Location: Valley of Sin

Route & General Observations

We went for tour into the Valley of Sin to investigate the persistent slab problem.


Avalanche Details
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Trigger SkierRemote Trigger No
Avalanche Type Soft SlabAspect Northwest
Elevation 3700ftSlope Angle 35deg
Crown Depth 18inWidth 25ft
Vertical Run 80ft  
Avalanche Details

We triggered a small persistent slab avalanche. This avalanche occurred where an glide avalanche had previously released, and was filled back in with wind drifted snow. This avalanche failed on large depth hoar 6-8mm. This area had snowpack that was much shallower than the surrounding slopes and a low friction bed surface.

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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

We had collapsing and cracking at ridge tops during our tour.

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

It was cold, clear and calm during our tour day. No new snow was observed.

Snow surface

Snow surfaces were a mixed bag today. Low density surface snow and knife hard wind slab could found in a relatively small distance. Snow surfaces were faceting with the cold weather. Some areas hold soft wind pressed snow.


We dug one pit today. Where we dug we found a old pencil hard wind slab sitting above weak faceted snow. In our tests we had failure beneath an old faceted crust on 3-4mm facets. This location had poor structure, moderate strength, and propagation results. Hand pits and pole probe showed similar structure in some areas during tour today. Distribution of these hard slabs seems to be patchy.

Pk 4068
3100' NW 26°

ECTP21 failed 60cm from the ground on 3-4mm facets
PST 35/100 END 20211028, on the same layer noted above.

Photos & Video
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