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Thursday, February 18, 2010

[MCR] Conditions in the west monashees

I am working in the western Monashees just south of Three-Valley gap and just NW of Monashee Pass.

To follow up posts by Jorg and Mark, we are seeing the same thing over here. On my first day of work (Feb 14) I skied 13 runs and between me ski cutting, my group remote triggering, sympathetic releases from avalanches we triggerd, avalanches triggered by the cat as it drove on hard packed flat roads in runout zones we had about 20 avalanches. Things have continued more or less in that vein each day since. Most of these avalanches were small but mostly that was because we were skiing in very small terrain features and on runs that had been heavily skied prior to the last snowfall. Places that have not been heavily skied are producing size 2.5 avalanches (big enough to ding a pickup pretty good and certainly big enough to kill a skier or sledder) on 20 degree slopes. There are many reports of bigger avalanches in areas around us.

Here we have 3 layers of surface hoar in the top 60cm with the latest one (Feb 8th) being most reactive. Here's some notable observations:
 - We are seeing deep and rough tracks in the bed surface, so old ski tracks are meaningless.
 - Unless it's been heavily skied and it's very moderate terrain, we are seeing recent ski tracks in the slab, so recent ski tracks are highly suspect.
 - We are seeing avalanches on 20 degree terrain so the 30 degree rule is out.
 - Today I triggered an avalanche 35cm deep x 40m wide by 50m long on the Feb 8th layer and the 4th skier across the bed surface triggered a second slide where the bed surface avalanched on one of the deeper layers. So skiing on the bed surface is no guarantee of safety.

There's been some natural activity but not nearly enough to clean out all the pockets and all the layers. Over the last four days, it's been getting a bit harder to trigger these things: on the 14th you just had to approach a slope and it would take off, today it's often the 3rd or 4th ski cut and part way down the slope before it'll go. And the slides we are seeing getting a bit bigger every day. North and East aspects above about 1500m seem to be worse but we've triggered slides on most aspects and elevations over the last few days.

I am skiing only in terrain where I know every detail intimately. I am skiing only on VERY small terrain features where I always have a safe exit option. I'm staying off all convex or unsupported terrain over 20-25 degrees. I'm avoiding terrain traps like the plague. I'm becoming more conservative every day.

Given how shallowly this layer is buried, it is producing impressive results in terms of propagation and avalanche size. It will likely remain unstable for a long while yet. The average active life of surface hoar like this is 3 - 5 weeks and that's in a normal winter.

If you want to post this message elsewhere or wish to pass it on, please do so freely.

Take care and be safe out there.

Karl Klassen
Revelstoke, BC
karlklassen@telus.net