Crystal Lakes

Variability was the name of the game today. Very little escaped the wind overnight, and we found a wide range of surface conditions: Sastrugi, stout crusts, breakable crusts, ice, wind skin, wind board, and occasional pockets of soft snow.  We went hunting for wind slabs, but came up empty as all we could find were signs of wind erosion. That snow had to have blown somewhere, but we couldn't find it. We suspect it was lurking mid-slope somewhere.  As such, we found no obvious signs of instability, just challenging skiing and skinning.

What we observed today was a great example of the complexity of the interaction between wind and topography. Though the overnight winds on Crystal Peak were SE and up to 60 MPH, we ascended a north facing bowl that was completely wind-swept by due north winds. This slope was stripped down to the old surface and revealed wet avalanche debris from the rain event on 12/7. On an adjacent slope, the wind had blown from the east.   

The Crystal zone will certainly benefit from an upcoming refresh!

In wind-exposed locations, the 12/7 is at the surface as the wind blew what ever soft snow there was away. On other south-facing slopes that are more sheltered from the wind, there is a sun crust from the prior few days. On lightly wind affected northerlies, we found a thin wind skin capping 4-6" of settled storm snow over the 12/7 crust. After that wind event, there is hardly anywhere outside of tight trees that has no wind effect.

In locations with soft snow at the surface, we dug down to assess the bond to the crust below. Hand shears took moderate force and revealed a fairly consolidated slab that is pretty well bonded to the 12/7. There is some weak snow both above and below the crust.

We dug a quick pit on a west aspect at 6350'. This was in a very wind-exposed location, as noted by the HS of 135 cm compared to sheltered areas at the same elevation which have significantly more snow on the ground. We performed a single compression test which yielded a CT 13 Q2 down 10 cm on weak snow above the crust. The 12/7 crust itself was quite friable and decomposing in this location.  Boot pen was to the 12/7 crust.

0-10 cm - Wind Skin to 4F to 1F

10-12 cm - 4F 

12-14 cm - 12/7 MF Crust - friable

14 - 32 cm - 1F to P

32-34 cm - 11/24 MF Crust - P

34 - 52 cm  - P

All in all the snowpack is strong and well-consolidated, with the potential exception being just above the 12/7.