How to Perform an Extended Column Test
The Extended Column Test (ECT) is a snow stability test that looks at both fracture initiation and snow propagation. Both are needed to cause an avalanche. Most stability tests only examine fracture initiation, or how much force is necessary to cause an avalanche, but propagation is how big an avalanche is going to be. Both initiation and propagation are important information to know when making decisions in avalanche terrain. The extended column test is similar to the snow compression test and it will help you make smart decisions when you are in the backcountry that could save your life.
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Instructions
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Find a safe place where you can test the snow pack. Ensure that you are out of any avalanche paths or other dangerous situations and that the location you want to test is a similar aspect to where you want to ski.
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Dig a snow pit that is a meter wide across the slope and a meter deep in the snow using your shovel and identify any weak layers in the snow pack. Weak layers may cause the snow to be unstable.
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Measure 30 centimeters upslope from the back of the snow pit wall. Attach your snow saw to your pole and cut the back section and sides to form an isolated freestanding column that measures 30 centimeters upslope by one meter across the slope.
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Place your shovel face down on one side of the column. Tap your shovel ten times from the wrist, ten times from the elbow, and ten times from the shoulder, like a snow compression test. This simulates avalanche initiation.
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Watch the column and record on what tap the column breaks, or propagates. The tapping represents initiation and if the snow moves or slides across the weak layer it represents propagation of the snow. If the snow propagates with only a few taps, it is a "red light" or dangerous situation. if the snow does not propagate, it is a "green light" or safer situation.
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Tips & Warnings
Be sure to perform several tests to ensure accurate results. Make decisions based on more than one type of stability test, experience, weather observations, avalanche forecasts, and your own avalanche education. Ensure that when you saw through the column you have a clean cut that is deeper than the weak layer you want to test. Seek out avalanche education before you venture into any backcountry situation. Be sure to make smart decisions.
Do not disturb the snow where you are performing the test (ie - don't walk or ski on the snow). Do not base your decisions solely on the extended column test. If you don't feel comfortable performing this test, you can learn more about it by taking an avalanche course. Your responsible for yourself and your friends whenever you are in avalanche terrain.
