Observation: Turnagain

Location: Head of Lyon Creek and Pastoral/Sunburst, Turnagain Pass

Date:

February 17, 2016 6:31pm

Observer:

Jeremy Allyn Professional

Route & General Observations

Toured up into the head of Lyon Creek today (2/17) via Center Ridge. Turned around on our NW asp run near 3400ft as winds began rapidly transporting loose surface snow. Yesterday (2/16), we climbed Pastoral’s standard route (descended same) via Taylor Pass and skied out via Sunburst’s W asp from north of the summit.

Contact, Location & General Observations

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Forecaster Comments

Winds in this area are known to be confusing due to proximity to glaciated terrain. Sometimes varying wind directions can be experienced at lower elevations, and can be different from the dominant ridgetop NE flow that was present all day (Feb.17) at Sunburst Weather Station. Below is more info after a follow up question about the observed SW wind observation.

" think todays winds we experienced were a bit basin specific...very down slope and sinking. Although looking up valley and to the SW I did see some blo snow off high ridges."

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

Lots of recent avalanches observed in both zones - generally D2 wind/storm slabs that ran naturally from high on ridge crests in the alpine, with many triggered by cornice fall. No avalanches observed in the lower alpine or treeline elevation bands.

Weather & Snow Characteristics

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

Weather

The biggest weather player today was a rise in moderate SW winds by noon - felt mostly in the alpine.

Snow surface

SH to 1cm observed from road to just above Treeline on today's route, as well as on summit slopes of Sunburst yesterday. A bit of surface cracking during the onset of moderate SW winds today. Our uptrack (15-20cm deep) was getting filled in rapidly at higher elevations. Any SH that was in the Alpine was getting knocked down and buried by wind transport.

Snowpack

In general, I found the upper part of the snowpack to be quite variable the last few days, especially in the Alpine. Today's cold temps seem to be breaking down the storm snow/crust interface at 25-35cm. Wind press, wind slab, loose/faceting older storm snow, temp and wind crusts, some great settled powder - all this variability lowered my confidence resulting in more of a "pulling back" mindset.

Location

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