Avalanche: Girdwood

Location: Upper Crow Creek

Route & General Observations

Sunny day in the crow creek area. Highpoint of 3200′.

We witnessed at multiple wet loose slides entrain a lot of snow on steep solar aspects, initiating mostly from rollerballs off of rocks. They were certainly large enough bury a person, and a few covered old skin tracks. We actively witnessed at least four of these slides, one had gone before we arrived, and we were able to hear 2 more.
We also saw multiple wind slabs that likely released in the last 48hours. The were generally on NW facing terrain. Propagation seemed to generally be 100 feet wide, but running at least 1000′ in the steep terrain.
There also may have been a slab in the Magpie basin, but looked to have partly filled in.

Avalanche Details
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Trigger NaturalRemote Trigger Unknown
Avalanche Type UnknownAspect South Southeast
Elevation 4700ftSlope Angleunknown
Crown DepthunknownWidth 1000ft
Vertical Rununknown  
Avalanche Details

We saw a large slab near the head of the crow creek valley. See the attached marker in the general description for its rough location. It appeared to be around 1000' wide. The crown was maybe 2 feet deep but it was hard to tell as we where quite far away. It appeared to release above a bench feature which seems to have kept it from running to the valley bottom.

See general description for other avalanches.

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

Clear skies and strong sunshine for most of the day till high cirrus clouds moved in around 3:45pm.
Light winds from the south, not always present.
Temp at car upon our return was -2*C

Snow surface

We were able to get onto a variety of aspects today.
A very thin surface crust was present on all aspects up to our high point of 3200'. This crust was breaking down on solar aspects in the heat of the day. We skied a slope that was receiving solar radiation at about 1pm, and were able to get widespread roller balls that grew to microwave-sized blocks within 50 feet.
Otherwise, on non solar aspects we noticed small surface hoar. It was micro surface hoar at the trailhead (>1mm) but grew to be 2mm near our highpoint, sitting on the very thin crust.


Handpits were our only tests today. We again found the same two crusts mentions on 2/17 Raggedtop ob, but buried a little deeper. This time the upper crust was reactive, shearing with easy force, breaking just below the crust, about 45cm down. We performed a hasty ECT at our Highpoint, on a WNW aspect. ECTN26 failing just below the aforementioned crust.
It is hard to tell, but this may be the culprit for the larger avalanches happening in the region. We were able to highjack a previous group's snowpit, and in terms of structure, it was the only layer of concern within the upper snowpack.

Photos & Video
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