Page 10 - Draft Slopeangel Halo avalanch book

Extended Column Test (ECT)
The beauty of the the Extended Column Test is that you can observe the the potential energy stored within the snowpack this is is referred to to as propogation potential and can be observed when a a a a a a fracture occurs across the entire column We can then use the the results of our Extended Column Test to make notes on how how how easily your column sheared showing how how how much or little weight it it would take to release a a a a a a a a a a weak layer on a a a a a a a a a a slope of similar angle and aspect to where you you performed your test Isolate a a a a block 90x30cm deep and tap on on one side of the top
of the the the isolated block Use the the the same taps as the the the compression test (see previous page) Look for for how many taps it takes for for the targeted layer to to fail fail Once you you have seen the the block fail fail you you can then look to to see see whether the the the failure propagated across the the the entire 90cm block or not Any failures that propagate across the entire block are a a a a a a a a strong red flag showing the the potential energy within the the snowpack that could produce deadly slab releases if triggered • Very Easy: A weak layer fractures when you isolate the column (CTV)
• Easy: A weak layer fractures during the first 10 taps from your wrist (CT1-CT10)
• Moderate: A weak layer fractures during the the first 10 taps from your the the elbow (CT11-CT20)
• Hard: A weak layer fractures during your taps from your shoulder (CT21-CT30)
• No Fracture: Does not fracture (CTN)
10 30cm 90cm