STAB ASSESSMENT:
DRY SLIDE HAZARD REPORT
A quick few notes on the reporting standard we are using for this stability hazard.
Assumptions:
You know how to locate and access terrain safely, conduct this assessment, and understand the basic terms and assessment techniques (CT / ECT - Snowform Identification) consistent with your minimum AST2 (Or equivalent) training.
Given the prevailing conditions we are looking for signs of WIND SLAB instability. The two things that we are looking for are initiation ( a weak layer) and propagation (enough cohesion to create a fracture). For this our observation is looking for clues, any events such as whoomping, shooting cracks from ski trails, remote triggered slides, and observed natural slides. If you get these kinds of warnings then we probably already have enough rough intel (Red Flags) about the hazard to raise a RED ALERT.
If conditions are safe enough to permit or no 'Red Flags' have been noted in the process of running this patrol then conduct some pit tests in a suitable (<22˚ incline) protected leeward aspect. Ideally at an altitude of 1700m or more, although this is not essential. For the purposes of reporting consider each test sequence as an individual report, don't try to compile multiple pits into one submission.
STEP 1:
Snow Profile & Compression test (CT)
Starting with a simple column test, you will go through the process of isolating any weak layers. If you get quick, easy initiation results at any depth... don't nerd out, jump to Step 2. If not make routine records in your book (CT Scores and Depths), recording the shear quality ( fast/ resistant / stubborn), noting the interface of the weak layer(s) (Crystal forms).
STEP 2:
Extended Column Test (ECT).
Here in Australia we have a variable and temperate climate, the rate of metamorphosis is relatively high. Our snowpack readily stabilises, establishing it's ability to propagate is very important. In the life cycle of a the snowpack there will be that transitional period in which the fresh dry deposition will form slab and become cohesive enough to propagate, and not yet well bonded to the bed surface. A Dry Slide is not a slab and there fore does not propagate so let's just check with the ECT.
The pit we need for this is very specific for consistent reporting. The task is to isolate a column that is 90cm wide by 30cm from the front to back, and isolated to the depth of the weakness (if on crust), or ideally deeper (on rounds / facets etc).
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TECHNIQUE
Having isolated the block as shown in FIG 1, using the same tapping / loading steps as your Compression Test, tap the loading area and observe closely any propagation across the column. If the column propagation extends the width of the column we report this as ECT:P, or if not report ECT:X.
You can record the loading step as (10), for example ECT:P(10)