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Observation: Mt Aire

Observation Date
12/29/2019
Observer Name
Wilson, Hardesty
Region
Salt Lake » Parleys Canyon » Mt Aire
Location Name or Route
Mt. Aire
Weather
Sky
Obscured
Precipitation
Light Snowfall
Wind Speed
Calm
Weather Comments
Cold, calm, and snowing very lightly.
Snow Characteristics
Snow Surface Conditions
Powder
Red Flags
Red Flags Comments
No red flags
Comments
Mt. Aire can have a thinner and weaker snowpack than the tri-Canyons, so we wanted to have a look around. We went up Snowdrift (peak to east of Mt Aire) to dig a couple pits. Our highest pit was at 8,440' (that's just under the ridgeline up there!) on a north aspect. While there were basal facets evident, the weak layer is so close to the ground that it is interrupted by rocks and shrubs. Moreover, the 2.5 mm facets were damp where they weren't frozen, and several extended column tests gave the same reassuring result: no fracture, no propagation. Probing in a few spots the structure seemed similar to where we'd dug: 105cm was a representative depth, and only around rocks did the probe drop the final few centimeters as it will with basal facets. We skied steep north and east-northeast. If we had hiked up the other side to Mt. Aire proper we would have again pulled out probe and shovel to look for shallow snow and poor structure.
At lower elevations where the snowpack was shallower (60-80 cm) the slab itself was transitioning to small-grained facets. There was not a distinct "weakest" layer. No basal facets, and no results on a compression test.
We used a shovel tilt test to see if there were any clean weak layers within the new snow, and nothing sheared easily. Only with hard taps and a steep angle could we get snow to slide on top of or below the thermal crust (now 18cm down). If we get a good load with the upcoming New Years storm, its possible we'd see activity around this crust.
At this point, the low density new snow with large stellars seem to be the "weakest" snow and may step down 6-10" onto the crusts on the off aspects. Surface hoar not noted, but may have blended in with the large dendrites...
Today's Observed Danger Rating
None
Tomorrows Estimated Danger Rating
None
Coordinates