 Poster: A snowHead
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Just reading through Free skiing.
It implies that after heavy snowfall, you shouldn't be looking to ski north facing slopes as these are at the most risk of avalanches as the new layer has not bonded to the underlying one. South facing slopes, because in the sun, and the snow melts, refreezes, etc. it will bond quicker.
Something about the powder spring snow cycle and looking for the right snow at the right time.
Any thoughts? Not sure if I understood that section correctly...
Oh...also said never to cut the snow above people below you. Does this mean you can't cross other people's tracks if someone is below you or that you should not make heavy turns when directly above people?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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GordonFreeman,
It is mostly about bonding properties. You don't want weight on a flackey layer or rotten snow so south facing might not be good either.
I think it helps if you know what the snow was like the previous week/day. You'll see plenty of sluffs on sun drenched slopes through out a sunny week....
Veritable minefield here..
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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?
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a very big minefield indeed..... but the simple answer is it isnt that simple. a magazine probably doesnt give enough in depth detail and you would be better to read up some proper books on the subject and then take a course with a guide....
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You need to Login to know who's really who.
You need to Login to know who's really who.
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skimottaret, Free skiing is a very detailed book on the matter by Jimmy Oden but I agree a course is a good idea. I was just trying to make sense of some of the text but as always a couple of reads will be needed. I believe the idea was that things don't bond/settle til a few days after fresh snowfall but the powder --> spring snow cycle was mentioned which occurs over a certain time period depending on conditions.
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Anyway, snowHeads is much more fun if you do.
Anyway, snowHeads is much more fun if you do.
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Not withstanding the vagarities of snow types and weather, a good starter is not to be in the way of the things should they happen. It is far easier to see where the danger may be than to guess or understand what the snow might do. Spot choke points or terrain traps, register places where slides have started and under what conditions and aspects....bla bla...
minefield again...!!
Some of these books can be really scary, that once read, you wonder why we go off-piste at all.
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You'll need to Register first of course.
You'll need to Register first of course.
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Yes, the sun can help with a melt - refreeze to get bonding. In the depths of winter, the sun doesn't get strong enough to make enough of a difference though.
It also has to do with wind loading, in Whistler, the winds generally come out of the south-west, swinging occasionally to south-east. therefore the northern aspects are also the lee sides, which means the get wind loaded ( the wind blows snow over the top of ridges from the south, and the snow drops down onto the north side ) so that can also raise the avy risk, it also makes them more desirable to ski 
There are no hard and fast rules when it comes to preventing avys. All you can do is use common sense, and take extreme care if in any doubt as to the stability.
As to skiing above people, I presume you mean other parties, because people in your party should be skiing down to pre-determined SAFE spots. If other people are hanging around below you, it is safer to not ski cut above them, wait for them to move, or ski another slope ( or traverse away from them or something ) then get to a safe spot and catch up to them, and give them a bit of a talk about mountain safety, about not hanging around ( especially in groups ) in terrain that is unsafe, either naturally, or from the possibility of other skiers.
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The main point is that north faces are colder. It isn't just about melting and refreezing. Snowflakes will bond with those around them even if they do not melt through a process called "sintering". The colder this is, the slower the process. At -20 degrees it almost stops
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| wbsr wrote: |
As to skiing above people, I presume you mean other parties, because people in your party should be skiing down to pre-determined SAFE spots. If other people are hanging around below you, it is safer to not ski cut above them, wait for them to move, or ski another slope ( or traverse away from them or something ) then get to a safe spot and catch up to them, and give them a bit of a talk about mountain safety, about not hanging around ( especially in groups ) in terrain that is unsafe, either naturally, or from the possibility of other skiers. |
But surely you shouldn't cut the snow above a predetermined safe spot either? You stop nearer the sides don't you usually? I think the impression was that as you ski down you shouldn't ski directly to the safe spot and stop because this cuts the snow above the safe spot, you should come into it sideways. Is that true?...or logical for that matter.
| Arno wrote: |
The main point is that north faces are colder. It isn't just about melting and refreezing. Snowflakes will bond with those around them even if they do not melt through a process called "sintering". The colder this is, the slower the process. At -20 degrees it almost stops
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So...if it has just dumped it down, would you ski a north slope at 9am in the morning if it is between a 30-45 degree angle (common avalanche angle)?
Yet late in the afternoon on sunny, warmer days, you should be avoiding the wet/rotten snow most likely on east and south facing slopes?
Doesn't the powder --> spring snow cycle occur on a daily basis and also over a number of days?
Aspect, angle, and elevation all come into it at some point so I agree the questions are somewhat vague but just trying to get a bit of discussion round it 
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brian
brian
Guest
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| GordonFreeman wrote: |
So...if it has just dumped it down, would you ski a north slope at 9am in the morning if it is between a 30-45 degree angle (common avalanche angle)?
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If it has just dumped it down then wind direction is far more important . As said above, north facing slopes are colder, so tend to stay dangerous for longer following snowfall. However, as you've just pointed out yourself, it's only one factor among many. Every situation has to be judged taking all factors into account. North facing slopes can be the safest ones if it's warm enough for wet slides.
The Swiss avalanche bulletins are quite good for giving explanations of where's dangerous and why.
http://www.slf.ch/avalanche/bulletin-en.html
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>> But surely you shouldn't cut the snow above a predetermined safe spot either?
My take on this is that before you ski a pitch you should be aware of possible escape routes and also your "stopping" point. This should be outside of any potential run off, but not hidden. The people you are skiing with need to see you, and then you need to see them when they ski.
You are correct that you shouldn't cut across a slope to the stopping point, ( in theory - in practise people tend to do this) rather make your way towards it as you ski the slope.
regards,
Greg
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Most slides happen on East- and North-facing slopes above 2000m in the afternoon when the avalanche-risk is rated around 3.
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And love to help out and answer questions and of course, read each other's snow reports.
And love to help out and answer questions and of course, read each other's snow reports.
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This is such a complicated subject I'm not going to try to answer properly (I'd be here all afternoon even with the small amount I know). You really need a book as others have said.
The largest danger is from wind slab, which forms on lee slopes and hollows (even a very slight hollow). If there has been high wind it can form even if there has been no new snow and can persist under newer snow. Prevailing winds in the Alps are from the South and West so lee slopes normally face North and East (but not necessarily and remember that wind can be funnelled by valleys and gulleys).
Wet snow avalanches can be dangerous too, late in the afternoon when the sun has softened old sun facing crust ,and water has has percolated to become a lubricant on a deser layer or on the ground. Guides are usually much more cautious in the afternoon on hot days for this reason and also because they don't like leaving big ruts in the snow which freeze at night and spoil any possibility of spring snow skiing
Whitegold, Do you mean avalanches which involve people? Most avalanches are spontaneous or deliberately triggered and don't catch anyone.
Last edited by And love to help out and answer questions and of course, read each other's snow reports. on Tue 5-02-08 14:42; edited 2 times in total
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snowball -- Yes, involving people.
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You know it makes sense.
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The problem is often put in the form:
North (and NE) facing slopes have the best snow but also the most danger.
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Otherwise you'll just go on seeing the one name:
Otherwise you'll just go on seeing the one name:
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The more I larn bout avalanche risk - the more I know I have yet to know. 
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Poster: A snowHead
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| GordonFreeman wrote: |
| skimottaret, Free skiing is a very detailed book on the matter by Jimmy Oden. |
sorry i thought you were refering to a magazine not the book 
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