Avalanche: Turnagain

Location: Seattle Ridge - Flats and lower uptrack

Date:
Observer:
Route & General Observations

Checked out the Seattle Ridge side of the Pass today – goal was to get a look at the motorized up-track in and the avalanche conditions there.

Avalanche Details
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Trigger NaturalAvalanche Type Unknown
Aspect UnknownElevationunknown
Slope AngleunknownCrown Depthunknown
WidthunknownVertical Rununknown
Avalanche Details

Two recent avalanches:

1- Glide on Seattle Ridge. Photo below. This glide likely released sometime on Feb 4th or early on the 5th. It is half way between on the motorized lot and the motorized up-track on Seattle Ridge.

2- Pete's South slab avalanche. This slide also released sometime between Feb 4th and early on the 5th. No photo. It looks to have been a wind slab roughly 2-3' deep, 100-300' wide and running ~500'.

Poor visibility hampered views of MUCH of the terrain so we have little information on natural avalanche activity.

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)?Yes
Observer Comments

Other than the recent avalanches we had reports of shooting cracks above treeline.

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

Snowfall, heavy before noon then tapering off and warming up. Light to gusty Northerly winds along the Seattle Ridge East face. Temperatures in the low 30's at 1,000'.

Snow surface

Very wet and saturated snow at 1,000'. ~6-8" of new from 2/3. At 2,000' there is ~2' of new dense snow. Another party we talked to reported ~3' of new (much drier) snow at 2,500' that was significantly wind distributed along the Ridge.

Snowpack

We dug several quick pits to suss out how well the new snow was bonding with the weak old snow that sits on a stout crust (this set up is from 1,000'-~2,500'+, this crust does not exist at the high elevation over 3,000').

Pit: 2,000', SE aspect: total snow depth 3meters. New snow 16" (40cm). Test results: ECTN 14 resistant planar at the new/old snow interface 16" down from the surface.

Bottom line: The snow was so warm and wet at 2,000' that bonding was occurring - good sign for these lower slopes... However, we were not able to access high enough elevations to assess the true start zones for slide paths such as Repeat Offender. Much uncertainty exists as to how well the new 'drier' snow is bonding with the crust at the 2,500' elevation.

Photos & Video
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