Observation: Butler Fork

Observation Date
1/28/2013
Observer Name
Greg Gagne
Region
Salt Lake
Location Name or Route
Butler Trees
Weather
Sky
Broken
Weather Comments
Some hints of blue showing late morning. -7C at 8800'.
Snow Characteristics
New Snow Depth
11"
New Snow Density
Low
Snow Surface Conditions
Powder
Snow Characteristics Comments
About 25 cms of soft, unconsolidated new in mid-BCC with dense graupel interfacing with the old snow surface. Despite the graupel layer, still easy to feel old crusts/tracks underneath. The graupel layer seemed well-bonded to the old snow surface and I couldn't get a clean shear with shovel-tilt test. However the light density snow in the top 20 cms (8") was sluffing very easily, failing just above the graupel layer.
Comments

Not-quite-dawn-patrol to Butler Trees. Overall feeling is there wasn't enough new snow or wind to overload any weaker layers.

I was finding the rain crusts from 1/24 at lower elevations with loose facets underneath, but the stout crust seems to have effectively bridged weak layers. My biggest concern at low elevations would be loose snow sluffs.

I have largely been traveling at lower and mid-elevation slopes the past few weeks and overall I have not been finding overly weak snow from our two January faceting events. Over the past 4 days I have been getting mostly CTN and ECTN scores. Where I have been getting a fracture, shear quality has been Q2/RP or Q3. Facets from the two January events are very-small grained (.5 mm) and appear to be turning to rounds. I think the absence of a temperature gradient early last week helped heal these weak layers at low and mid-elevations, especially in the cottonwoods where there has generally been a thicker snowpack.

Scores today:

  • ECTN (down 25 cms new snow/old snow interface.)
  • CT 23 Q3 (down 65 cms failing in early January facets.)

I haven't traveled enough above about 10,000' to get a sense of things at upper elevations.

Dug a pit at 8800' on E/NE aspect (photo included) showing recent layers in the top 75 cms (30") of the snowpack.

Overall was finding a generally moderate danger with the greatest risk being sluffing in the new snow.

With snow and wind in the forecast, am expecting conditions to change.