Observation: Logan

Observation Date
3/7/2013
Observer Name
Weed
Region
Logan
Location Name or Route
Steep Hollow
Weather
Sky
Broken
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Mild temperatures again. Fairly light westerly winds. Periods of warm sun-clouds-periods of light snow....
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments

Around a foot of new snow blown into upper elevation flats since Sunday..... Only a few inches of new snow on a supportable sun-crust on south facing slopes. Pretty nice powder conditions in sheltered shady terrain...

Red Flags
Red Flags
Wind Loading
Poor Snowpack Structure
Red Flags Comments
No obvious signs of instability. Weak faceted snow plagues many areas, especially at mid elevations and where the snowpack is shallow, but it appears dormant for the time being.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments

Wind slabs appeared fairly well bonded today and cornices weren't very sensitive. I dropped one refrigerator-sized cornice chunk onto a steep drifted north facing slope and only produced a small new snow sluff.. Drifting from overnight southeast winds will probably build new wind slabs and thicken existing slabs in lee north and northwest facing terrain.

Avalanche Problem #2
Problem
New Snow
Problem #2 Comments

My experiences with faceted snow have mostly been bad, and despite lack of much related avalanche activity this winter, there are many areas plagued by the stuff. It's worst where the snow cover is shallow, like in the trees or along exposed ridge lines, but appears widespread at mid elevations and east of the Bear River Crest in the northern and eastern parts of the Logan Zone. The weak layers lie dormant for now but might be reactivated by a sudden addition of weight or a rapid rise in temperature, and both scenarios are possible in coming weeks as we head into springtime.

Snow Profile
Aspect
Northeast
Elevation
7,900'
Slope Angle
32°
Comments

I found varied snow structures and test results today up in Steep Hollow. This short video shows a propagating failure in an extended column test, with the failing layer faceted snow from early January....

Video

Faceted snow in my Steep Hollow snowpit at around 7900' on a north-northeast facing slope.

Coordinates