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Start by isolating a column about the same size as the blade of your shovel, in other words, about one foot by one foot (30 x 30 cm). Be sure to completely isolate the column. Then take the blade of the shovel and lay it flat on top. Finally start tapping progressively harder on the shovel blade until the column fails. Start with ten taps by articulating from your wrist, then ten more taps by articulating from your elbow, then ten more from your shoulder using the full weight of your arm. Don’t push your arm into the snow, but let it fall with its own weight. In this way, the test is somewhat quantifiable. In other words it doesn't depend on “feel” or the opinion of the tester, but it has a reproducible number which is more or less same for most people and can easily be communicated to others. For instance, it failed on an easy tap from the elbow, or it failed on a moderate tap from the elbow or perhaps a hard tap from the shoulder. Since snow stability is dependent on the size of the trigger required to make it fail, this test is especially easy to interpret. Of course, if you have an unusually light arm or an unusually heavy one, you need to take that into account.

Writing Up the Results: Note: write up the score on the trail report has it relates to what number of Articulations the snow breaks on: Example if the snow Breaks when you are articulating from the elbow on the Fifth articulation  you would score it has a   CT 16 ( Yellow Light)  If the snow breaks when articulating from the wrist on the second blow then you would write it up as:  CT 2 ( Red Light)

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Compression Test Info + Video   Forest Service