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Avalanche: Other Regions

Location: Snug Harbor to Lost Lake

Date:
Observer:
Route & General Observations

Rode from Snug Harbor to Lost Lake and the new Lost Lake weather station site (~3miles NNW of Lost Lake). Encountered a snowmachine triggered wind slab en-route – details below.

Avalanche Details
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Trigger SnowmachinerAvalanche Type Hard Slab
Aspect EastElevation 2500ft
Slope AngleunknownCrown Depth 18in
Width 300ftVertical Run 200ft
Avalanche Details

Snowmachine triggered wind slab by a party earlier in the day on a short but wide slope in the gully of Martin Ck. Looks to have been triggered while descending from above. Presumable no one caught or carried. Slab did propagate quite wide - 300' wide and running 200', the length of path. Crown was 1-2' deep.

Natural wind slab seen on a SE face just above Lost Lake. Around 1-2' deep and ~200' wide, running ~3-400'.

Red Flags
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Obvious signs of instability
Recent Avalanches?Yes
Collapsing (Whumphing)?No
Cracking (Shooting cracks)?No
Observer Comments

Active wind loading all day. Natural wind slab avalanche and one human triggered.

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

Partly sunny skies, temperatures in the single digits and strong NW winds. Ground blizzard made travel difficult at times. Many plumes seen off peaks. Winds blowing all elevations except for the most sheltered areas.

Snow surface

Wind damaged surfaces - scoured, sastrugi, wind drifts. Only in the Lost Lake trees did we find some softer snow out of the wind.

Snowpack

Dug one pit in the Lost Lake trees in a sheltered zone - 2000', East aspect, ~15 deg slope. Roughly 16-18" of soft snow (Fist to 1F hardness) over a 1" layer of weak facets that sit on the mid Jan crust. ECTP 19 Sudden Collapse. A layer of buried surface hoar sits ~12" down and a few inches above the facets but this layer was not reactive.

Poor structure exists in the Snug and Lost Lake riding areas.

Photos & Video
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