Avalanche: Hatcher Pass

Location: lower microdot

Date:
Observer:
Route & General Observations

Went for a short tour below microdot, it was very windy. We saw recent avalanches, had lots of collapsing, and large shooting cracks. The wind has taken its toll at the upper elevations.

Avalanche Details
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Trigger SkierAvalanche Type Hard Slab
Aspect WestElevation 3400ft
Slope Angle 42degCrown Depth 24in
Width 80ftVertical Run 40ft
Avalanche Details

While putting in a skin track we remote triggered two avalanches. The first avalanche was D1 in size and traveled maybe 35'. the second avalanche was D2 in size and failed 200' feet away from the first avalanche. It seems like they happened at the same time. The crown at the larger avalanche was up to 3' deep in places. A good reminder that an avalanche on even small terrain features can have dangerous consequences.

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)?Yes
Cracking (Shooting cracks)?Yes
Observer Comments

Really big shooting cracks, some traveled at least 200'. Lots of large collapsing, you could feel the whole snowpack drop a couple centimeters at times. Strong too extreme winds were transporting snow very quickly. A natural avalanche near ridge top could be observed on the up-track for the Ray Wallace chutes.

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

independence mine parking lot 10:30am 27°F overcast, S-1, Moderate East wind.
Very strong winds reduced visibility to almost zero at times. Flagging and plumes on ridge tops was quite impressive.

Snow surface

The snow surface was a mixed bag today, 1F hard wind slab in some areas, 4F snow in others. At times when breaking trail the snow was at least 3' deep. in some areas the wind had eroded the snowpack down to the basal facets from October.

Snowpack

We dug pits in two locations. one was a quick crown profile on a remote triggered avalanche. The other pit targeted the basal facets to see how they adjusted to the new load(see photo below). The snowpack has poor structure, low strength, and very high propagation potential.

Above the sledding hill,
Crown profile
3400' W aspect 42°
HS 130
ECTP1 @ 35cm 1F wind slab

3600' W aspect 15°
HS 65
ECTN4 5cm from surface, 4F wind slab
ECTP14 15cm from ground basal facets
ECTP13 15cm from ground, basal facets
PST 40/100 End on basal facets

Photos & Video
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