Compression Tests on Donner Summit

We conducted several compression tests as part of a snow science experiment on Donner Pass today. Our controls were 3 standard compression tests (2 on a shaded North aspect with unconsolidated snow under a half inch sun crust, and 1 on a sunny South West facing aspect. None of these tests showed any breaking or failure. For the experiment, we sprinkled 5 or 10cm of snow on top of a column, let it sit for 20 minutes and then tapped the column to test it in the normal fashion. 

Results:

The shaded North aspect:

with 10cm of new snow added to the top of column, we saw repeatable, easy, nearly Q1 results all breaking just underneath the half inch surface crust. (CT4, CT2, CT5)

with only 5cm of new snow added, we did not see any failures (CTX, CTX)

Sunny South West aspect

with 10cm of new snow added to the top of column, we saw varying levels of reduced instability (CT17 Q3 25cm below the surface, CT24 Q3 just on top of the artificially buried surface snow. 

We spent about 10 minutes looking for faceted snow just underneath the crust on the shaded North facing aspect with a hand lens and crystal card, but could not find any crystals with oblivious square edges.