Pits – Base of Hillman
By John Sidik | Synnott Mountain Guides
Date of Observation: March 5, 2020 1:30 PM
Location of Observation: Approach to Hillman/Edge of avalanche devastation
We preformed a number of compression tests, one extended column test and one propagation saw test on a small east facing hill, sheltered by trees, near the avalanche devastation below Hillman’s Highway. While the nature of the terrain may not represent some of our popular avalanche paths, I have been finding similarities with pole probing and hand shear tests in other drainages.
Shovel tilt showed failure between the most recent wind slabs.
Compression tests yielded a number of results:
CT14 BRK down 15cm on graupel w/ 4F wind slab above
repeat of test showed SP fracture on same layer
CT17 SP down 55cm – facets between two ice crusts
confirmed with a repeat
No layers showed signs of propagation in ECT
The most evident weak layer was 55cm down; a 2cm layer of what looked to be a mix of small facets and decomposing graupel, but had begun to to stabilize (picture below). Despite its weak appearance, and upside down layering, this layer showed no signs of failure or propagation in CT, ECT or PST (PST 80/100 End down 55cm). The layer was present in two pits; one today, and one Wednesday afternoon near the hermit lake caretakers cabin.