Techfiles - Page 1
March 28, 2008 @ 2:07 PM
Words by Melanie Schönthier, Photos by Alex Roberts
The following story is fictitious but if you often ride in the backcountry it could easily turn into reality for you. Have a look in the Open Mic section in issue 96 and you will find out that even pros do not always detect dangerous situations. Avalanches are incalculable but with some knowledge and some experience you can reduce the risk.
As Tom wakes up at the crack of dawn this February morning, he can hardly wait to get on the mountain as it looks to be a bluebird day. It had snowed for three consecutive days and now 30cm of fresh powder just waits to be shredded. Tom quickly checks the avalanche report – danger level 3. “I will be more cautious today and avoid the steeper run,” he tells himself. But his promise is almost forgotten when he meets his friends Alex, Mike and Lisa at the valley station and they manage to bag the first gondola.
Last year they visited an avalanche camp together. After several hours they’d already learnt a lot: how steep a slope has to be to become dangerous and how you find and dig out a buried person. Furthermore, some myths about avalanches were cleared up. “If there is a ski track in the slope it doesn’t have to mean that there won’t be any avalanches,” mountain guide Christian had explained to them. “And to race down in front of an avalanche only works in one out of a hundred cases.” Throughout the whole winter, Tom and his friends had practised with their beacons from time to time, and now they felt safe when going into the backcountry. But today they ignore an important warning sign – over the last few days the temperatures not only dipped below zero at night but it also stayed very cold throughout the whole day. Thus the fresh powder couldn’t really bind with the old snow cover. As if somebody has put Vaseline between those two layers, this time bomb waited for the smallest concussion to race down.
When the group arrives at the mountain station, they switch on their beacons. It is only a short hike up to the summit from where numerous runs lead down to the valley. They start with some easy runs first. Nothing beyond 30 degrees, as 97 percent of the avalanche accidents happen in slopes that are steeper than this. Tom remembers this number from last year’s avalanche course. There he also learnt how to estimate the steepness of a slope: if you can see an alpine touring skier’s switchbacks, the slope is at least 30 degrees; if you need to jump round during the run, it probably is 35 to 37 degrees; and slopes interspersed with rocks are around 39 degrees.
The group gets more self-assured with every powder run and risk riding the steeper slopes. Experts call this a ‘feedback effect’. It is about 1pm when Tom suggests riding a wide, south-facing chute that he had already kept his eye on for some time. He guesses that the run is about 35 degrees steep, but at least it is not north-facing. During the avalanche camp, their mountain guide had hammered into them the fact that 70 percent of avalanche accidents happen on slopes exposed to the north, and that they could cut the risk in half by avoiding these runs. When they arrive at the top of the chute, Tom notices a small wind-lip that extends into the drop-in. He recalls that his guide had always called the wind the “builder of avalanches”, but Alex just laughs. “Come on, there has never been an avalanche on this slope. It will be all right!” It’s a fatal mistake that a lot of freeriders make.
