Avalanche: Douglas Island

Location: Mt. Jumbo Bowl

Date:
Observer:
Ed Shanley Professional
Route & General Observations

Toured up along the east side of the bowl topping out at the obvious saddle on the ridge.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect NorthElevation 2400ft
Slope Angle 39degCrown Depth 24in
Width 60ftVertical Run 250ft
Avalanche Details

While decending, I purposefully made a hard turn on the ridge above a steep convex wind loaded slope. Given the rapid settling and shooting cracks on the adjacent slope it was not surprising when the avalanche occurred. I was impressed by how quickly the slide picked up speed and that it ran ~400 meters down the surface of the bowl.

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)?Yes
Observer Comments

Poor hand shears, collapsing, shooting cracks and recent ongoing significant snowfall.

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

2000’ cloud ceiling, heavy snowfall, 24f, light and variable winds.

Snow surface

New Snow

Snowpack

Probing while traveling showed an average of ~35 of new snow although recent accumulation of over 1 meter of new snow was seen in multiple places. The variability in new snow depth and obvious wind waves indicated recent wind transport of the new snow.

Quick hand shears showed poor bonding within the new snow that was slightly more compact, upside down, at the surface.

In a more formal snow pit, there was no propagation observed in an ECT but multiple breaks under the shovel within the top 100cm of snowpack.

On slopes adjacent to the slide collapsing and shooting cracks were observed.

Photos & Video
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IMG_0230  

Location