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Observation: Skyline

Observation Date
2/8/2013
Observer Name
Darce Trotter/ Steve Cote
Region
Skyline
Location Name or Route
Cotton Creek Ephriam Canyon
Weather
Sky
Overcast
Precipitation
Light Snowfall
Wind Direction
Southeast
Wind Speed
Moderate
Weather Comments
Snowing increased as the day progressed, becoming moderate as we exited about 2, but we came down out of it and clearing to west may mean things would lighten up again
Snow Characteristics
New Snow Depth
2"
Snow Surface Conditions
Powder
Snow Characteristics Comments

Most noticeable layer was an annoying zipper crust down a couple of inches in general. Thicker on Flats and more southerly aspect, but prevalent almost everywhere including even most north aspects. Probably formed due to very warm days and is now buried just beneath the surface up to 4" down.

Beneath that next 20" very strong settle rounds sitting on another crust that was about 2" thick, then from there down the pack is larger grained and slightly weaker for another 20" to the old facet crust lasagna

I went into this detail here because my pics were very poor due to flat light.

Red Flags
Red Flags
Wind Loading
Red Flags Comments
the zipper crust will be the first player as a failing layer or possible sliding surface when new load is added, and because we were looking at a fairly thick pack, the rest of the snow remains strong in the area we were in, but we still ran across some weak faceted snow that we sandboxed through in the trees where the snow as very well protected
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments

winds are already cranking,and where we were, direction was SE, which we found a little odd. Shallow wind slabs with cracking was already starting in the pillows off ridge lines

Avalanche Problem #2
Problem
Persistent Weak Layer
Trend
Same
Problem #2 Comments

cannot ignore recent past, in extreme terrain with shallow pack, faceted snow on ground remains in the back of our minds, we looked for areas with thicker snowpack and kept our slope angles near 30.

Snow Profile
Aspect
Northwest
Elevation
9,800'
Slope Angle
31°
Comments

a look at our stability tests, sorry for poor light

Video

we found skiing pretty good, despite the loud zipper crust, but it would thicken up on flats and threatened to throw us over the bars.

Don't feel deep slab was an issue in this particular area. The crust will not take much to activate it, did not noted faceting just below it, but snow sitting above it is weaker.

Coordinates