Hard and soft wind slabs on the east side

By Ryan Matz | MWAC Forecaster

Date of Observation: December 10, 2018  12:00 PM
Location of Observation: Tuckerman Ravine and east snowfields

Large areas of hard wind slab yielding hard but clean failures in stability tests, with smaller and fewer areas of soft wind slab which remains reactive, producing easy and clean failures.
Able to intentionally skier trigger the small pocket of soft wind slab on a test slope as pictured.
Weak layer of concern for both hard and soft slabs seems to still be a density change in snow deposited since the 12/3 crust was formed, with bonding to the crust remaining good.
The bonding to the crust is good where wind has all but scoured to the crust, too, masking what would be easy to see grey, exposed crust with a thin layer of white. Visual observations are challenging in this way and also in determining what is soft or hard wind slab.


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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