 Poster: A snowHead
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Im sure i watched a film of Ross Hewitt and company skiing last week and at the beginning of the film it showed one of the gang scoop up a hand full of Hoar crystals?? Hopefully the correct name for them and I was wondering if these conditions we are having now are the perfect ones for producing the problematic weak layers for later in the season, hopefully someone will know how long it takes for them to develop.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Pretty much as you watch. So I don't actually know as I have not sat around watching it, but I think it forms quickly, within an hour or two. Typically you see it (in BC) in the late afternoon as it's cooling down. I guess the air has a fair bit of moisture from sun during the day and as the sun goes down the temperature drops quickly, bringing the amount of moisture the air will hold down. As that condenses out (not sure if that's the best term - the reverse of "sublimates" anyone?) it forms crystals which are typically large. I'm not sure precisely what governs the typical/ maximum size, but it's huge compared with the structure of the snow itself. Hence the mismatch when you try to get it to form up.
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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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@philwig, I know in previous seasons recently early season snow then lack of it for the next couple of weeks up to a month has seen significant problems with this I just wondered if its heading that way.
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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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I haven't seen any surface hoar this season but I've seen a lot of facetted snow, I posted a video on the snow conditions thread where the whole snowpack at the top of a couloir comprised these type of crystals. Round here you normally get surface hoar at lower elevations (frequent between 1000-1800m) where it is sheltered, there isn't any snow at lower elevations at the moment in France where I'm based so no surface hoar.
By the time it snows next the whole snowpack on north sectors could be facetted crystals. So expect a lot of 2/4 days where the avalanche risk rises from 2 to 4 at around 2200m where the current snow can be found. It could surprise a few people but not snowheads 
Last edited by You need to Login to know who's really who. on Tue 6-12-16 20:58; edited 1 time in total
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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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I@davidof, is this only relevant to north facing slopes or can this be a problem on all aspects?.
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You'll need to Register first of course.
You'll need to Register first of course.
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You'll get to see more forums and be part of the best ski club on the net.
You'll get to see more forums and be part of the best ski club on the net.
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That looks pretty terrifying to me and has given me a much needed kick up the back bottom to educate myself better this season.
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Interesting info I really need a course to go on to get so knowledge into me. Thanks@davidof,
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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If you look at the Tremper book (Staying Alive in Avalanche Terrain) he explains things very well. For slope aspect see P78. For Switzerland he gives N -> NE -> E as the critical aspects.
It is worth reading his book but there is really too much information to retain everything. Guide Olivier Mansiot says that carefully reading the avalanche bulletin for your sector and keeping off slopes they warn against is the most important factor.
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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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Thanks I will have a look for that and local knowledge is always a given and taking any warnings given seriously I am always cautious and probably sometimes over cautious and thats another good reason to educate myself more as im probably missing out sometimes.
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Just noticed this after posting similar photos in the general thread.
Deep in a shaded valley in Tirol that gets no sun at this time of year:
I assume this is the case on shaded N slopes at altitude too, but haven't been up to look in a few weeks.
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You know it makes sense.
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@clarky999, thats the stuff Ive seen recently im glad Im not going mad 
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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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| clarky999 wrote: |
I assume this is the case on shaded N slopes at altitude too, but haven't been up to look in a few weeks. |
That looks like surface hoar, I assume it was the crystals sitting on top of the snow? It is depth hoar (gobelet) and near surface faceted snow on N slopes at altitude at the moment formed by a temperature gradient in the snowpack. Surface hoar tends to form at low to mid altitudes - below temperature inversion (which is probably why Clarky found it) or near the dew point.
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