Avalanche: Juneau Mainland

Location: Thunder Bowl

Route & General Observations

Went looking for low-angle slopes where we wouldn’t feel the firm layer below the new light snow. This area seems thin this year, including below treeline on the approach, and at ridgetop where the winds have been stripping the snow and in some cases the ground is showing. The skier’s left side of the bowl (faces more east) is especially wind-stripped.

On the approach, skis went on and stayed on at 900ft, about 45 mins in.

Snow quality was excellent from 1800ft to 2400ft. Above 2400ft it was still good but much more variable and you had to identify the textures to maintain good skiing.

Avalanche Details
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Trigger NaturalAvalanche Type Soft Slab
Aspect West NorthwestElevation 3200ft
Slope Angle 38degCrown Depthunknown
WidthunknownVertical Run 1000ft
Avalanche Details

Saw multiple wind slab avalanches that had come out of extreme overhead terrain in Thunder Bowl. It was hard to tell the age because of the rapid snow transport going on. They may have been from the ongoing wind event, the last storm, or the last wind event, but they looked recent. They appeared to be thin from below, but ran far.

Also numerous loose dry slides in steep terrain. The new snow sliding easily on the previous firm 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)?No
Cracking (Shooting cracks)?No
Observer Comments

Rapid wind loading.

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

Clear, cold, windy

Snow surface

Pristine powder at 1800ft (15cms of new snow 15cms of overlying previous soft storm snow). Transitioning to variable wind-affected surfaces above 2400ft. Good skiing from ridgetop to 1000ft.


Very thin at ridgetop and on any proud/large features in the bowl due to wind stripping. In some wind-affected places the recent crust is showing, in other places grass is showing.

Photos & Video
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