Digging in the Snow

BY CJ Svela

APP Board Member since 2011

With contribution from Mattly Trent, Bear Valley Ski Patrol Director

There is a lot to be said about digging in the snow to analyze the pack and observing stability. Everyone has their own way of doing things, and their own techniques and tricks. A good habit to start with prior to sticking your head in the snow: analyze the weather, make observations on the drive up to the mountain, and maintain knowledge of the season’s snowfall and weather.

I always get asked “how many snow pits do you do in a season?” My reply is “It varies.” During my time working with the Canadian company Dynamic Avalanche Consultants in the North Cascades as an industrial avalanche technician, it was expected to dig a pit almost every day and to tour the surrounding elevations to analyze and observe the weather and snowpack. This was to mitigate a remote worksite that depended on open roadways to get supplies in and out to sustain the work camp. As a past observer for the Northwest Avalanche Center’s (NWAC) Mt Hood region, I had a goal of touring 2 to 3 times a week, planning around storm systems and periods of heavy traffic in the backcountry. I didn’t always do a snow pit on my observation days. Observing and feeling the snow and looking for recent natural activity, I completed a series of “Hasty Pits” with a goal of 10-15 minutes’ maximum for each. If I saw or felt something that needed more attention, that is when I went into the deeper observation of a full data pit versus a hasty pit.

When out observing either for patrol or on my own, I try to do a full pit analysis once a week. But every day I’m looking at the weather and keeping a journal of current conditions. The biggest thing is to develop a tuned second sense of how the snow feels under your skis. During your daily work constantly observe the specific test slopes and trouble spots your mountain’s terrain to judge what hazards may develop higher on the hill. Watch and listen for the classic and earie sound of “Whoomphing!” underneath your skis, and of course look for wide spread cracking being initiated by your ski tracks. Natural activity is huge sign of instability.

New tools and technology such as Avatech/Mtn Hub’s SP2 Probe and Scope Pole make it easy to get a “sense” of what layers lie beneath and helps you to make determinations while on the move. These tools are great and save time during the tour but they don’t replace sticking your head in the snow and feeling hands-on with stability tests.

Basic components to digging a snow pit: picking a representative slope & elevation, angle of slope, aspect of the pit & slope, and knowing the relativity of the sun to reduce solar exposure of crystals within the snowpack. Snow pits should be detailed yet efficient, thorough yet relatively quick. A lot of courses, American Avalanche Association's’ AVPRO course along with American Avalanche Institute (AAI) and AIARE, often preach the 1 hour rule for a full pit profile. Being quick and efficient is key to limiting your time exposed to the elements on a storm day.

Items to think about to prepare for digging a pit:

    • Your avalanche essentials: beacon, shovel, probe, and partner that knows how to use them.
    • A common objective or goal for the study day.
    • I carry an extra ruler, inclinometer and thermometer with my field book, separate from my study kit, so I can quickly measure and write notes. Often keeping these items in my tools compartment of my pack or in a cargo pocket in my pants.
    • When you get to a site to dig a snow pit, release your inner OCD. Keeping in mind to be detailed yet efficient.
    • Near Tree Line or Below Tree Line: a general rule of thumb is the height of the trees should be equal to the distance away from the trees.
    • Break out your probe to feel for a snowpack without obstructions such as rocks or trees.
    • With a partner, practice your conveyer or strategic shoveling technique. This will make good time digging your snow pit by saving time and energy along with practicing to dig out an avalanche victim.
    • The act of shoveling in the snow can tell you a lot about the structure. Is it soft, hard, icy? What layers are prominent in the pack?
    • Embrace your inner OCD by making right angles in your pit. Choose a study sides (that is shaded) while keeping the front the mainstay for stability tests.
    • Get in the habit of doing a series of 2 Compression Tests (CT) and an Extended Column Test (ECT) as a mainstay of every pit.

There is a lot to keep in mind while doing snow observations. Many factors go into gathering data relevant to making sound forecasting decisions. Always bounce ideas and thoughts off your colleagues. Form a Mentor – Mentee relationship to learn, educate, and form ideas together to help your understanding of this ever-evolving science. Ask questions of your snow safety directors, forecasters, and always learn. If you’re in the backcountry, choose your partners wisely.

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