Wind slabs, upside down snow structure in Huntington Ravine

By Jeff Fongemie | MWAC

Date of Observation: February 9, 2020  11:00 AM
Location of Observation: Fan of Huntington Ravine

First clear day after snow event Thursday and Friday. Overall, snow surface is a mix of finger to pencil wind slabs up to 50cm thick, and also to a much lesser extent exposed melt freeze crust that formed during the February 6-7 storm. This 1cm crust appears to be widespread. Digging into the snow in a few locations, we found an upside down snow structure above the MFC. Just above the crust approximately 10 cm of fist hard snow is topped by 30 cm or more of finger to pencil hard wind packed snow. Boot penetration in the slab ranged from supporting a person with little impact to boot top penetration. Various stability tests varied from ETCP 12-14 to CT failing on isolation, always failing on the soft fist layer of snow above the ice crust. We skied the slope.


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.


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