Observation: Days Fork

Observation Date
1/30/2020
Observer Name
Greg Gagne
Region
Salt Lake » Big Cottonwood Canyon » Days Fork
Location Name or Route
Days Fork Alta -> BCC
Weather
Sky
Overcast
Wind Direction
Northwest
Wind Speed
Moderate
Weather Comments
Moderate gusts from the NW in the morning, to very light winds by midday. Poor lighting with obscured skies, followed by a period of sun, with clouds returning afterward. Gotta love mountain weather.
Snow Characteristics
New Snow Depth
2"
New Snow Density
Medium
Snow Surface Conditions
Powder
Dense Loose
Wind Crust
Snow Characteristics Comments
Settled storm snow since late is about 30 cms (12") with ~5 cms overnight. Snow at the surface is dense which makes for easy travel and fast riding conditions. Some sluffing of the top few cms on steep northerly aspects.
Comments
Overall a stable snowpack and no big concerns for Friday. Today I visited the slide reported from Wednesday in Days Fork between Two Dogs and Oingo Boingo (Observation). This was on a very steep (> 45 degrees) N-facing slope at 10,000'.
Was rather surprised to see this slide that failed on a layer of facets that likely formed over this past weekend, and the dense slab was 30-40 cms thick (12-16") and wind-loaded in places. ECTP14 on two pits adjacent to the crown, failing on the layer of faceted snow underneath storm snow from this past week.
What surprised me was on Tuesday in Cardiff Fork I could not find any weaknesses at the new/old snow interface, and after getting full propagation on extended column tests adjacent to the crown, I dug several other pits on northerly aspects throughout Days Fork and all pits were ECTN with no clean shears. This makes me think Wednesday's Days Fork avalanche was an outlier, and this snowpack structure of preserved facets underneath storm snow is very isolated.
The only other thing of interest was sluffing in the top few cms of storm snow on steep northerly aspects in Main Days.
Today was my field day ahead of forecasting on Friday morning. Given the bump in wind speeds overnight into Thursday morning, and the slide in Days Fork on Wednesday, traveled with Moderate caution in mind today, looking for sensitive wind drifts. Overall wind drifts were very shallow and not widespread, And after digging extensively throughout Days Fork, I could not find the structure of preserved facets underneath recent storm snow, so am thinking Days Fork avalanche was a very isolated incident.
Today's Observed Danger Rating
Moderate
Tomorrows Estimated Danger Rating
Low