Avalanche: Hatcher Pass

Location: Avalanches near Stairstep/ Arkose ridgeline

Date:

March 29, 2020 9:59pm

Observer:

Allie Barker Forecaster

Route & General Observations

Recent natural large avalanche today near Stairstep/Arkose ridgeline, approx 3500′ NNW aspect. Strong winds all day formed wind slabs that likely stressed deep persistent slab. Avalanche ran over 2000′ to the creek bed. The snowpack (and our community) has yet reached another tipping point.

Note: The Waterfall path (Arkose area across from Skeetak) ran on 3/20 (pictures below). The avalanche is the video below is a different avalanche and was observed on 3/29. HPAC will investigate today to gather more accurate information.

Contact, Location & General Observations

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Forecaster Comments

This avalanche should get the hairs on the back of your neck to stand up if corona hasn't already done that.
Of particular note: We haven't seen a large avalanche like this on a NNW aspect since 3/4. All the avalanches we've observed over the past month have been on E to S to W aspects.

Avalanche Details

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Trigger	Natural	Remote Trigger	Unknown
Avalanche Type	Soft Slab	Aspect	North Northwest
Elevation	3500ft	Slope Angle	unknown
Crown Depth	unknown	Width	unknown
Vertical Run	2000ft

Avalanche Details

Preliminary report of a new natural avalanche today. If you have more information, please contact us.
Two avalanches were reported near Staistep/ Arkose ridgeline across from Skeetak. First avy was on a NNW aspect 3500'(see video)
The second avalanche was reported on an opposing angle on a SW aspect at 3500' (see pic)
This event is separate from the Waterfall path that ran, in a similar area, also to the creek on 3/20.

Red Flags

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Obvious signs of instability

Recent Avalanches?	Yes
Collapsing (Whumphing)?	No
Cracking (Shooting cracks)?	No

Observer Comments

Recent avalanches from strong ENE/ESE winds and slab formation throughout the day.

Weather & Snow Characteristics

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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.

Snowpack

No pit data.

Photos & Video

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SW and NNW 3500 Stairstep avys 3.29

avy stair step

Location

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