Avalanche: Hatcher Pass

Location: Punk Spines near Arkose/Stairstep

Date:
Observer:
Route & General Observations

3/30 Natural avalanche on W/NNW aspect 3800′ Punk Spines . Likely wind slab/persistent slab. Ran 1000′ to the gully.

Avalanche Details
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Trigger NaturalAvalanche Type Unknown
Aspect West NorthwestElevation 3800ft
Slope AngleunknownCrown Depthunknown
WidthunknownVertical Run 1000ft
Avalanche Details

Observers saw this from the road. Winds were strong Sunday/Monday contributing to new winds slabs that overloaded the persistent weak layer on all aspects, most obvious in the Arkose ridge area where Matanuska winds were considerably stronger for a longer duration.

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

3/29 and 3/30 Recent avalanches after strong winds build wind slabs, overloading the persistent slab. Largest avalanches in the Arkose ridge zone where Matanuska winds were strongest.
More natural and snogo triggered avalanches were reported, with many close calls, on the Willow side 3/29 and 3/30.
Few avalanches observed in IM bowl as a result of less wind on 3/30.

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

Strong winds starting early Sunday morning at 1am. ENE/ESE 16-23 G 34-51 for about 15 hours at 4500' on Marmot. Winds were likely stronger than reported on Arkose ridgeline, to the south of Stairstep where avalanche occurred.

Snow surface

10" soft snow in protected locations from 3/21 available for transport prior to winds 3/29

Snowpack

no pit data

Photos & Video
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