Observation: Turnagain

Location: Seattle Ridge

Route & General Observations

Seattle Ridge to Main Bowl (2800′)

Red Flags
Red flags are simple visual clues that are a sign of potential avalanche danger. Please record any sign of red flags below.
Observer Comments

Spoke with another group who felt a collapse along the ridge. They also reported digging a pit and finding propagation potential between a slab/facet combo.

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

Temps: Mid to high 30's F
Wind: 20-30mph g-40mph
Sky: Clear and sunny
Precip: None

Snow surface

Variable surface conditions depending on aspect and elevation and exposure to the wind
Eastern Face of Seattle - Supportable melt/freeze crust in the morning and smooth corn snow in the afternoon below 2000'
Eastern aspect above 2000' to top of the Seattle Ridge - variable 3" old wind slab with sun crust on surface. There was also very scoured areas as well as Sastrugi along the broad open ridge.
Shaded Northern and Western aspects - average of 8" of low density snow (with some near surface faceting)
*Surface hoar growth(4mm) was found on Northern and Western aspects, but only in places protected from today's 20-30mph winds. Surface hoar was not found below 2500'.


Dug a pit on a NNW aspect in an area protected from the wind. We found a layer of buried surface hoar 21" below the surface just underneath a 3cm thick rain crust. The BSH layer was standing upright and was reactive in our tests. Results showed propagation potential, but required moderate to high force to initiate the weak layer. PST30/100 (55cm below surface) ECTP23 (SC) ECTP24 (SC)

*This pit was dug in an area known for its surface hoar growth due to its protection from the wind and isn't representative of all NNW aspects in Turnagain Pass. BSH has been found in other areas, but isn't as widespread as the facets that have been well documented over the last weak. We did find on older layer of facets 10 cm below the BSH (laying just beneath another thin crust.)

Photos & Video
Please upload photos below. Maximum of 5 megabytes per image. Click here for help on resizing images. If you are having trouble uploading please email images separately to staff.