1/3 NWAC Avalanche Forecast

"Slopes up to 40 degrees were skied with no adverse consequences!"<br> -NWAC<br><br>Is it just me or does this seem like an odd way to approach avalanche forecasting?

holy taken-out-of-context batman!

My recollection is that the forecasters get much of their first hand reports from area pro-patrolers. It's not unusual for those folks to ski cut steep slopes and relate results to their peers. So it looks to me like one of their comments got quoted. Doesn't really seem that odd to me.

Hazard forecasting (estimating) is multi-faceted. Field observations, weather data, snowpack data, avalanche testing, hazard mitigation (bombs, guns, ski cutting), etc. are all part of the total estimate. The snowpack is also infinitely variable, there is sometimes a change from little or no hazard to significant hazard in a few feet of distance and slight aspect change, even on a similar angle and elevation because of sun or wind effects, anchoring, etc. A slab that rests on an obvious weakness often may have inherent strength thus anchors, slope shape (support below), etc.- many factors may result in no avalanche activity from such an obvious weakness when skied. <br><br>However, the same elevation snowpack may avalanche just around the slope under different specific conditions. Sometimes the force of the skis or even bomb will not be transmitted down to the weakness (depending on the H2O content and resultant communicating air space characteristics, inherent slab strength, etc.), thus no release. However a shallow part of the slab (rock below etc., wind or sun effects), heavier skier/ skinnier skis, or bigger bomb may transmit energy down to the weakness causing release (or even a few minutes or hours' warmup causing melt to add weight or weaken the bonds). A couple of examples that I can offer include bomb placement and force transmitted by ski cutting. I have followed up on avy chutes that have had a bomb placed, put another in a nearby location but on the correct aspect (wind and sun effects) and had the chute avalanche. Also, I am heavy and developed a ski cut technique that involves whipping the ski tails forcefully, sometimes resulting in releases where others could not cause a release.<br><br>Ski cutting, or ski testing, is a method of both hazard evaluation and hazard reduction. Having done it on the job in the past, I continue to do both constantly in the bc- it is an ingrained habit. There is some skill and knowledge involved, although one could figure it out- many skiers ski cut. One of my partners has learned about ski cutting with me and had a bit of fun when I have directed him, "cut there and it should go" and it does.<br><br>Hopefully my comments are helpful and/or inspire curiosity that results in study and observation. Even after many years' FT experience in avy work, I continue to study and observe so that I may stay alive on avalanche terrain. Have fun, but I recommend knowing why one is skiing a great run safely rather than guessing, assuming and hoping that it is ok. Aside from that, I believe that one needs an escape plan in the event that your estimate is wrong.

Thanks for sharing your thoughts, Randonee. What you wrote coincides with much of what I've learned from watching and talking with ski guides up in Canada as they go through their day. One in particular talked about finding little terrain features to test cut on both the ski up as well as the ski down - things like snow-covered boulders with steep edges or small unsupported steeper slopes (e.g. a roll above a tree well). While he gathered other data (e.g. pits) as well, he seemed to be rapidly getting much more information from doing these cuts on various aspects and in various sorts of positions. I've learned to do this ever since, and combine what I see with what else is happening that day.<br><br>However, an interesting challenge is how rarely my groups get anything of significance to slide (which is good, don't get me wrong...), which makes it a bit tough to calibrate the results of our tests. I guess if we're erring on the side of safety that's OK, but still, the sort of experience you got as a FT safety guy was clearly incredibly valuable.

So going more off topic: how exactly does one ski cut? I have heard it talked about, read about it, and even tried what I think is a ski cut myself (but never got anything to slide.) I'd love to hear from some experts exactly how to do one.