Northern San Juan

A handful of old avalanches, all above treeline in steep terrain.

Blue sky, WARM day, with calm to light breeze out of the north. South-facing snow surfaces were wet and sloppy by noon.

In Alta Lakes, I dug a snow pit on a northwest-facing slope near treeline and found a 100cm snowpack composed entirely of cohesionless facets. A thin melt freeze crust was found under the most recent snow, but it was decomposing and breaking apart. The snow towards the ground has become large-grained depth hoar averaging 4mm in size. Conducted an extended column test with ECTX results, no cracks, no propagation. I dug another pit in Alta Lakes below the Birthday Chutes, at 11,800 feet on a northeast-facing slope above tree line. The snow height here was only 70 centimeters, composed of several crusts with facets in between, over very weak snow depth from the Christmas crust down to the ground. I performed an extended column test and got a propagating failure on the 15th tap right underneath that Christmas crust. Finally, in Bear Creek, I dug in a spot I already visited earlier this winter and got very similar results three weeks later. This pit was dug on a northeast-facing slope above tree line at 12,400 feet. There is still a very stout crust from the Christmas rain event buried about halfway down the snowpack, but here it was much thicker and stronger than what I saw in Alta Lakes. In an ECT, I got no results, but with a very extra blows, I did get it to propagate below the Christmas crust on depth hoar chains (ECTP36, non-standard). As this crust breaks down in the shallower areas above treeline, it could allow future loads to cause failures below the crust where it sits over very weak depth hoar.