Avalanche: Turnagain

Location: Tincan

Route & General Observations

Toured up to Tincan common to look for avalanche activity and check out how the new snow is bonding.

Avalanche Details
If this is an avalanche observation, click yes below and fill in the form as best as you can. If people were involved, please provide details.
Trigger UnknownRemote Trigger Unknown
Avalanche Type UnknownAspect Unknown
ElevationunknownSlope Angleunknown
Crown DepthunknownWidthunknown
Vertical Rununknown  
Avalanche Details

There were about 5-6 recent avalanches on the SE aspect of Seattle Ridge at at 1500-2500'. They appeared to be wind loaded and were all on similar aspects and similar terrain features. The largest one was about 150-200' wide and ran down to the start of the uptrack, covering some recent sled tracks. The others ranged from roughly 50-100' wide. We only saw them from across the valley, but would guess they were 2-3' deep.

We also saw some large avalanche debris fields at the base of Tincan Proper, that had some new snow on top. Which indicates they likely released during the storm on Tuesday or Wednesday. We did not have the right angle to see the start zones.

On the S face of Eddies we saw several more natural avalanches that released across gully features in the steep terrain behind the Eddies head wall. These were approximately 50-100' wide and propagated down slope along ridge features. We couldn't see the debris so it is hard to estimate the size, put they were definitely large enough to bury a person (at least D2).

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

Mostly sunny skies and calm to light winds. Temperatures were cold in the morning, probably teens F, and warmed up to the low 30s F when we left around 4pm.

Snow surface

A new layer of surface hoar on the surface, with about a foot of ski penetration in soft snow below. Boot penetration was closer to 3'. On steep southern aspects the snow surface warmed up and it was easy to form a snowball with the moist snow around mid day.


We dug two snowpits along our route. One at 2200' on a S aspect and one at 3100' on a SW aspect. In both pits we had failures in our compression tests about 3' deep on facets around a melt freeze crust (CT 12 SC, CT 14 SC). Due to the southern aspect of both pits I think these crusts formed during sunny periods last week and were buried by the recent snowfall. In our extended column tests we did not get failures on these layers (ECT X). Due to the recent loading from 4' of snow over the last 3 days and the weak structure of these layers we still think they are concerning, despite not getting consistently unstable results in our stability tests. We also had some failures in the middle of the storm snow layer about 1.5' deep that are likely interfaces between warm and dry periods of the snowfall.

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.