October 25, 2014
Winter 2013 - 2014


Steps to perform an ECT
1. Isolate a column 90 cm by 30 cm.  It should be isolated 100-120 cm deep (about 1 meter) with straight, clean, and smooth sides.
2. Place your shovel blade on one end of the isolated column.  Either the left or right, it doesn't matter, just not in the middle
3. Apply a series of compressive forces to the shovel blade just as you would do for a compression test. 10 taps from the wrist, then 10 taps from the elbow, then 10 taps from the shoulder
4. Record the results and pay close attention when a fracture occurs across the entire column.  Fracture across the entire column is the propagation of a crack through the weak layer, a red flag.
Learn how to: Perform an Extended Column Test

Extended Column Test (ECT)
Extended Column Tests give information about both the initiation and propagation of a crack in a weak layer.  It is similar to the Compression Test except it tests an isolated column that measures 90 cm across the slope and 30 cm up the slope.

How to isolate the column
There are several ways to isolate a 90cm by 30cm column.
  • Place a probe or ski pole vertically in each of the two uphill corners of the column.  Place a piece of knotted cord around the two poles and pull both ends of the cord in a sawing motion.
  • Cut the two sides of the column with a snow saw.  Then attach the saw to a ski pole or other extension and cut the back with a vertical sawing motion.

Results
The key observation is whether or not a fracture occurs across the entire column.  If it does fracture across the entire column, this means the weak layer may is capable of propagating a crack across an entire slope thus producing an avalanche.  The question is then, how likely are you to initiate this fracture process.  Record results in the following manner:
ECTPV - A fracture occurs across the entire column (propagation) during isolation. A very ustable result.
ECTP# - A fracture occurs across the entire column (propagation) after some number (#) of taps.
ECTN# - A fracture initiates but does not occur across the entire column (no propagation) after some number (#) of taps.
ECTX - No fractures occur in the column after a total of 30 taps. Generally a stable result.
Always be on the outlook for signs of instability; one sign of instability trumps all signs of stability.
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