Avalanche: Turnagain

Location: Sunnyside/Main Bowl

Route & General Observations

Common uptrack with one small lap into main bowl, 10:45 AM – 2:00 PM

Avalanche Details
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Trigger UnknownRemote Trigger Unknown
Avalanche Type UnknownAspect Unknown
ElevationunknownSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

Numerous D1 R1 natural loose snow avalanches on a variety of aspects from the past 24 hours, ~2000-3000' in elevation, which looked to have generally run within new snow from 11/22 - 11/23. On a steep north aspect in main bowl, a few of these triggered some cracking... but without much propagation (see below). In this area of main bowl, most debris piles were covered by a few inches of snow, but a few were post storm. As pictured below, one slightly larger (~D1.5/R1) debris pile may have been the result of a slab on a west aspect below the Seattle Ridge weather station... but we couldn't get eyes on the start zone.

Some light skier triggered sluffing today on sunnyside. While ski tracks occasionally scraped the new snow down to the crust layer, these sluffs appeared to generally run within the storm snow, and not down to the crust.

One outlier to this small loose activity was seen across the arm to the northwest of Girdwood, where a large slab was observed back on the far skyline (see photo below).

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

Avalanche activity as reported above.

Moderate wind transport midday on high peaks back by Pastoral, Magnum/Taylor Pass, and Tincan Peak, with some transport well into the bowls below these mountains.

Weather & Snow Characteristics
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Temps around 20, light NE wind at ridgeline occasionally gusting moderate.
Few clouds in the AM, transitioning to broken skies with some low clouds by mid afternoon.

Snow surface

~1' of new snow from 11/22-11/23, with the north end of the pass appearing to be the winner. 26cm of new snow at both the Eddies and Sunnyside parking lots, with just 12cm of new snow at the Sunburst lot. Impressive surface hoar - 4-6mm - grew on a very delicate crust below 1500', with smaller but still substantial surface hoar observed all the way up to ridgeline, ranging from 1-4mm.

Along the route, 30-40cm of new snow in areas above 1500' that were wind protected, with some wind effect at ridgeline reducing new snow over the crust to ~10cm. We didn't encounter any location where winds scoured the new snow down to the crust.

Generally, the new snow/snow surface was dry today, even down at the parking lot level (1000'). The only exception was steep slopes directly facing the sun mid-morning, where just the surface snow was moist.


No formal pits/stability tests today, but overall it seemed like the new snow has bonded very well to the crust!

Photos & Video
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