Avalanche: Turnagain

Location: Pete's North

Date:
Observer:
Route & General Observations

We toured up to about 2200′ at Pete’s North and skied a few laps in the trees.

Avalanche Details
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Trigger SkierAvalanche Type Soft Slab
Aspect WestElevation 2100ft
Slope Angle 35degCrown Depth 6in
Width 100ftVertical Run 50ft
Avalanche Details

We were able to trigger multiple small wind slabs that formed as winds picked up for a few hours mid-day.

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

We saw a lot of shooting cracks on wind-loaded slopes that weren't steep enough to slide.

We met another group that got a large collapse as they worked their way up an existing skin track for their second lap of the day:

"At 1600' on a NW aspect, ~32 degree slope on Pete's North we heard a large collapse that propagated throughout the entire clearing in the trees... probably 75+ yards wrapping around us from the SW aspect to the North. This was on our second lap having put in the track earlier with no result, and after 8 people had also traveled on the uptrack. It occurred when a member of our party was just exiting a slightly tree sheltered area - total snow depth at the location was 140cm, with the new snow above the Dec 1 crust totalling just 50-60cm. We dug at this spot, and the 60cm slab started fist hard and transitioned to four finger+ (see photo below), sitting on a broken up super thin crust, with several centimeters of fist hard facets below that. This all sat on the stout crust that was ~5cm thick and pencil + hard. For test results, got a CTV, CT6 SC down 60cm, and an ECTP 17!" (From Andy Moderow)

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

Light snow for most of the morning until around 2:00 p.m., with winds picking up to 15-20 mph for about two hours before the snow finished. Winds calmed down and skies cleared at the end of the day.

Snow surface

About 4" new snow, sitting on top of another 6" or so of soft snow from earlier in the week. The newest snow buried a crust that only went up to about 800'. Winds were making fresh slabs about 6" deep throughout the day.

Snowpack

Our main concern was fresh wind slabs that were easily triggered with ski cuts. There was still plenty of snow available to make these slabs deeper if (when) winds pick up.

The more surprising find was the large collapse in the 12/1 facet/crust combo. This seems like an isolated incident at this point, but it is definitely worth paying attention to. Tests on this layer showed mixed results- ECTX (x3), ECTP17, ECTP26.

More snowpack info in snowpit profile.

Photos & Video
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