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.


ABOUT THESE OBSERVATIONS

Snowpack observations are one part of the complex puzzle which is your decision to enter avalanche terrain. Some observations may include stability tests. It’s important to understand that the results of a stability tests are seldom conclusive anywhere, but particularly in snow climates and terrain like ours where the primary driver of instabilities is wind drifted snow. Many stability tests exist and each works best with specific avalanche problem types. Stability test results should never be used alone as an indication that a slope or conditions are safe particularly when more obvious red flags are present. Please use this page as part of your information gathering process, but don’t make decisions based on a single piece of information. A good article that summarizes some of the issues associated with snow and avalanche observations can be found here.

The Mount Washington Avalanche Center cannot verify the quality or accuracy of any observations that come from the general public.

SUBMIT YOUR OBSERVATIONS

See an avalanche or evidence of previous avalanche activity?  Near-miss? Snowpack observations?

Your observations are valuable to an accurate forecast! We welcome observations from everyone. You don’t need to be an avalanche professional to submit helpful observations, just be as detailed and accurate as you can.