 Poster: A snowHead
|
Following on from the previous theads about off piste precautions and avalanche gear. Its all very weel carrying this gear, but I'd rather not get caught in an avalanche. So how do you know if a slope is safe to ski? Anyone heard of Rutschblock tests, shovel tests, or compression tests?
I bet quite a few of you have and I bet some of you probably know how to carry out some of these tests; I guess quite a few of you know what to look for when digging snow pit as well; but who actually does any of these tests when skiing off piste? For those who ski with guide, have you ever seen him/her do one?
|
|
|
|
|
|
Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
|
|
Kit, yes but I've heard recently that the snow pit isn't really of much use. Any views?
|
|
|
|
|
|
Well, the person's real but it's just a made up name, see?
Well, the person's real but it's just a made up name, see?
|
Here is a photo of from one of our snowpit from last season:
taken from this page http://www.pistehors.com/comments/282_0_1_0_C/
In reality you don't need to dig down more than about a meter as artifacts below this depth will be well enough bridged not to have an affect on slope stability. As David says, digging a single pit won't tell you if the slope will slide due to a phenomena known as spatial variability. A slope can really be viewed as a matrix of risk, faceted crystals may have formed above rocks or surface hoar may have been buried close to some trees. These are trigger points, the slope may only slide when you ski directly over one of these areas. That is one reason why guides like their clients to ski nice and tight tracks as it reduces the risk, if the guide has just skied a certain pitch without a problem he is probably reasonably confident that it won’t slide either side of his tracks.
Rutschblock, compression and snowpits where where backcountry travel was at about 10 years ago. These days people would be better off learning and practicing safe travel techniques in avalanche country.
A snowpit is still a useful tool. It can tell an experienced person about the snow over the whole season, something you would only get by being in area over the whole time. This can compliment other knowledge. In France, at least, most guides practice in their home areas so already have an intimate knowledge of the season’s weather conditions and the risks these will provoke on certain slopes. You will also see them probing the snow a great deal with their poles as they move around. That of course, doesn’t mean they or their colleagues, either other guides or avalanche forecasters haven’t already dug snowpits that week, just they didn’t do it with clients who are more interested in skiing or boarding than hanging around in the cold while a guide digs holes in the snow.
|
|
|
|
|
|
You need to Login to know who's really who.
You need to Login to know who's really who.
|
David@traxvax, I would say that you have to pepper the slope with snow pits to cover all aspects but I am not qualified to answer your question: I’ve spent a few days on mountaincraft courses; yes, I have carried out all those tests; I ski fairly regularly off-piste with a guide, I have mountaincraft and avalanche safety books; but an expert, I definitely am not. I just brought up the whole subject as it appeared to me from other threads that people appeared to be a bit blasé about the avalanche risks of skiing off-piste.
Sure, ski off-piste with a local guide, they know the area intimately; I do, wherever possible, it's a lot riskier skiing without one. Be aware of the risks though, even with a guide. Avalanches are indiscriminate with who they kill- they don’t recognise people who wear trancsceivers, or mountain guides, and then decide to divert their course out of homage. I have skied with guides who have experienced being completely buried by avalanches. Check the pistehors website for avalanche fatalities, including those of mountain guides.
davidof, Is there a fine line between off-piste and ‘backcountry’? As an example: near Andermatt there are pristine powder slopes just a few metres from the lifts, that head off in a direction away from the lift and require a long traverse to get back; these are very rarely skied, so would you call this ‘backcountry’? Does it matter?(These are not meant to be aggressive question marks!) As more and more people go further afield in search of that perfect, virgin powder slope, I would have thought that trying to assess slope stability using these tests go hand in hand with 'safe travel techniques in avalanche country’
|
|
|
|
|
|
Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
|
My Swiss mate's girlfriend works for the snow reserach lot in Davos and she reckoned that they had now decided that the pit method was a bit pointless - this was a couple of years ago. Apparently the Swiss mountain troops are getting to be of a similar thought - except that they can pepper a slope with pits, and if you're sticking a load of troops on a mountain side for a day or two, you might want to have some idea.
This is all anecdotal and second hand, though.
|
|
|
|
|
|
|
|
|
|
|
|
FAQ