Avalanche: Hatcher Pass

Location: Bennets Ridge

Date:
Observer:
Route & General Observations

Went back to site for observation from 4/28 to observe any changes in stability and to perform additional stability tests. While conducting snow pit tests on low angel terrain (19º) just off ridge top, snowpack collapsed and triggered avalanche below us.

Avalanche Details
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Trigger Foot PenetrationAvalanche Type Soft Slab
Aspect North NortheastElevation 4000ft
Slope Angle 35degCrown Depth 24in
Width 150ftVertical Run 800ft
Avalanche Details

Majority of path estimated at 35º steepness, pulling back to roughly 30º in one area.
SS-A-I-r-R3-D2-I

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?No
Collapsing (Whumphing)?Yes
Cracking (Shooting cracks)?No
Observer Comments

One collapse near pit site before second collapse which triggered avalanche. Note, the poor structure is now well hidden, but seem to exist on north facing slopes above 3500' (might also exist at lower elevations)

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

Several additional warm moist snow and graupel fell yesterday and last night. Flat light but some visibility today, no natural avalanches observed. Numerous density inversions within last weeks snow.

Snow surface

Moist new snow with lots of graupel.

Snowpack

Very similar to observation from 4/28, but weak layer depth had increased from 35 to 60 cm down. Stability results showed high variations in force to affect weak layer, but all ECT test propagated and CT test failed with sudden collapse. Performed 3 PST test all failed within PST25-30/100 End.
Snow from the last 10 days are not bonding well to near surface facets that exist on higher elevation shaded slopes.

Photos & Video
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