Sign Up for the Utah Snow and Avalanche Workshop (USAW) on December 7th!

Observation: White Pine

Observation Date
4/3/2022
Observer Name
Nate L & Jennifer W
Region
Salt Lake » Little Cottonwood Canyon » White Pine
Location Name or Route
White Pine
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Decreasing Danger
Problem #1 Comments
Dug a couple pits, one at 8750' and one at 9300' (profile below). At 8750', no distinct layer of facets was noted, despite digging to the ground (HS 150cm). This could be due to warming (the whole snowpack was moist) or this spot's exposure to wind. There was a small diurnal temperature gradient in the top 30cm of snow (around 2C/10cm) which did not seem to be causing any snow metamorphosis, as the top 30cm were comprised of a stout, unbreakable melt-freeze crust.
Our second pit (profile below) did contain plenty of facets from the Jan/Feb drought. However, it was clear that recent warming has locked up this layer pretty solidly. Again, all the layers in the snowpack were at least moist. The facets had lots of ice bonds (from meltwater percolating & freezing) between crystals and were much more rounded than last time I took a look at them, before the warm spell. These snow grain observations were confirmed by snowpit tests- a PST 75/100 and ECTX show a general lack of reactivity. It seems that we're probably done with our dry PWL avalanches for the season.
Avalanche Problem #2
Problem
Wet Snow
Trend
Same
Problem #2 Comments
Evidence of wet activity from the warm spell abounds across White Pine, with fields of rollerballs under every cliff band, numerous wet loose avalanches, and a few wet slab crowns. We did not observe any fresh wet avalanche activity. As evidenced by our snowpits and abundant crusts on all aspects, there was a solid refreeze last night. Ski pen remained less than boot-top, even in the evening (around 5). Many attempts to initiate wet loose slides on steep slopes via kicking with skis were unsuccessful. The snowpack seems to have gotten used to the heat, but I suspect that a particularly warm day or lack of overnight refreeze would cause wet activity to kick up again. Additionally, I think there's a lot of uncertainty regarding wet slab potential in the drought layer facets, and I would be particularly careful on warm days as the consequences of a wet slab would be very severe.
Snow Profile
Aspect
North
Elevation
9,300'
Comments
Clear, with light winds only on 11,000' ridgelines. All aspects except high northerly have some form of crust. Generally this was stout, thick, and unbreakable, but late in the day there were plenty of breakable crusts to be found on aspects that warmed up before going back into the shade. Additionally, this crust became more breakable at higher elevations and off-shady aspects (ENE, WNW, even low-angle NE-NW). Soft (sometimes even dry!) snow can be found on northerly aspects above 10,000', or in particularly well-sheltered spots from 9,000-10,000'. Coverage at low elevations is already too low to ski, with the entire south side of LCC looking Juneish and the exits to many of the northerly couloirs off North Thunder (Coalpit, Y) either very rocky or totally unskiable.
Today's Observed Danger Rating
Low
Tomorrows Estimated Danger Rating
Low
Coordinates