The Paradigm of the Extreme
There in some understandable confusion over how, if the hazard level was rated low throughout the Eastern Sierra, two people could have been killed by an avalanche this past week on Split Mountain. Over at ESAC, Sue Burak elaborates a bit on the subject in her May 1st advisory, writing:
"Avalanche advisories do not apply in extreme terrain for obvious reasons."
Though it is perhaps a remarkable statement, I find myself tending to agree. The Split avalanche was the subject of much discussion between me and my friends, particularly as we were flirting with high angle, high altitude terrain in the Whitney region this past weekend. In my opinion, the entire beacon-shovel-probe paradigm falls apart when you enter extreme terrain, in part because avalanches in fall-you-die terrain aren't likely to kill you by burying you.
In extreme terrain, avalanches become deadly merely via their potential to take you off your feet. Size becomes almost irrelevant. In the worst-case scenarios, localized instabilities act in concert with exposure to create hidden tightly-coupled systems—invisible mouse traps waiting to be sprung. Triggered at just the wrong moment, even the tiniest slab can be all it takes to knock you loose and send you to your doom.
In such high-consequence terrain, assessment becomes a constant task. Every variation of angle and aspect—indeed every shadow—will likely have its own microclimate. Thus, extreme skiers must enter and maintain a mode of continuous assessment, testing and measuring the snow by feel with every step, recording and memorizing each and every change for the trip back down.
Viewed within this paradigm, an avalanche forecast becomes at most only a minor factor in a complex and ongoing process of deciding when and where to ski—and how much risk to bear. It is perhaps the height of arrogance to believe it possible to control one's destiny when skiing extreme terrain. Experience, skills, and judgment are critical, but ultimately they are not enough. When we ski the extreme we are always playing a sort of roulette game—and hoping we don't get unlucky...
Andy Lewicky is the author and creator of SierraDescents
Dan Conger May 2, 2011 at 12:26 pm
You guys be sure to stay safe on your skiing adventures ... definitely don't want to be reading about you like this one day.
Kyle May 2, 2011 at 5:27 pm
I must say I disagree with this. To say that the avalanche forecast doesn't apply to extreme terrain gives the implication that it applies for all non-extreme terrain. Avalanche prediction is a science, and like all science there is much variation regardless of the terrain you are on. Avalanche forecasts shouldn't exclude extreme terrain, rather skiers should know that the snowpack of their current location may not be similar to the snowpack(s) studied to create the avalanche forecast. Also using extreme terrain is a very objective term. Many would call a couloir extreme terrain, however, if an avalanche occurs the couloir walls would contain the slide path and a skier would most likely be buried, not thrown off of a cliff.
I am not surprised that there was an avalanche when the rating was low. I was taught to be constantly looking for things that affirm and contradict the forecast. The avalanche forecast is just what I start my day out with, but it continues to change throughout the day even when I'm driving to the trail head because I know it cannot describe everything, again regardless of terrain.
Scott May 4, 2011 at 2:39 pm
What exactly do they mean by "extreme terrain", I wonder? To me that statement just sounds like them trying to avoid liability. Don't get me wrong, avy forecast centers shouldn't be held responsible for avalanches, just like weather forecasters shouldn't be held responsible for destructive weather; what I mean is that statement is rather devoid of meaning. There are those who would consider 90% of the BC to be extreme terrain, there are those who would only consider you-fall-you-die skiing to be extreme terrain. So which is it?
Kyle's got it right, the forecast is just a rough guideline and you should be constantly re-assessing as you go to gather more data and improve your knowledge of current conditions. There's still an element of roulette to all of it, but it decreases with more caution.