 Poster: A snowHead
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I know early snow is very liable to a sudden thaw but is there now enough depth for the base to be set in for the season.
Eg. A typical resort with 80cms lower levels and 200cms up top, if if didn't snow again this season, and temp remained "normal" would there still snow on the ground in April?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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Nothing typical about 80 cm lower slopes, but the answer has to be no. Fresh snow throughout the season is always needed, if only to keep the base from icing over. And if there is no snow then there must be some warm weather. But it does provide a 'guarantee' that with average snow later there should be enough for a good season.
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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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You need to Login to know who's really who.
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up4it, The lower-altitude snow in the Alps is, of course, always that at most risk. The higher-altitude snow tends to steadily accumulate through the winter, which is why snow depths above 2500m tend not to maximise until mid-April.
Heavy rainfall in winter (sadly not unknown) can dissolve snow very rapidly, and is not that unusual in resorts at 1000m or below.
On balance, that's why it's best to book skiing at relatively short notice for early-winter trips. You can enjoy fabulous conditions (as we see now). Heavy snow is generally very reliable for the spring on north-facing slopes above 2000m.
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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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snowball, but it's still the best early snowfall I've seen ever. I.e. since 1988. Let it snow (with stabilising intervals), Let it snow (with stabilising intervals), Let it snow,...etc.
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You'll need to Register first of course.
You'll need to Register first of course.
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| Quote: |
And if there is no snow then there must be some warm weather.
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well, not necessarily. It can be very cold and dry - though of course resorts can make snow in cold, dry conditions (provided they don't run out of water). But yes, obviously temperatures on lower slopes will tend to be higher, and dry sunny weather will also increase evaporation rates. You can see snow "steaming" in the sun - that means the depth is decreasing, and it can happen quite quickly. There are no guarantees at this point - half a metre of snow on lower slopes could disappear very quickly. Apparently 80% of snow evaporates, rather than melts (can't remember where I read that though).
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| up4it wrote: |
I know early snow is very liable to a sudden thaw but is there now enough depth for the base to be set in for the season.
Eg. A typical resort with 80cms lower levels and 200cms up top, if if didn't snow again this season, and temp remained "normal" would there still snow on the ground in April? |
yes, above 1500 meters, that is pretty much what happened last year.
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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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| davidof wrote: |
| yes, above 1500 meters, that is pretty much what happened last year. |
Looking at the records for Val d'Isere (random choice) to check this:
Snow depths on upper slopes went up (ie it snowed) till mid december, then there was a gradual slump till January, when it increased (ie snowed) every week. Then there was another gradual slump till a short way into March when it increased (ie snowed) over 2 weeks to the greatest depth of the season. Then it gradually reduced.
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I predict I will be able tell you in April. 
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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the pattern in the Beaufortain was similar to that snowball describes
This is the Meteo France "NIVOSE" record from last season. This is the official measurement of actual snow on the ground, in some suitable spot at 1633.
The picture is a bit small, but the steep decline in late December, after the big pre Christmas fall, is very clear, as is the steep decline during the "snow drought" in February. But there was a succession of falls in January and early February, that stupendous dump in March (as well as plenty of smaller dumplets throughout the month) and useful toppings up in April.
It's very clear from this graph that if the snow drought of early January had continued there would have been very little snow left by early February. If you look at the temperature graph above it's clear that the steep February decline was despite colder than average temperatures. If February had been a bit warmer, or if it had rained, it wold have been pretty disastrous.
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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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i think a lot of it is down to grooming and use of canons, the dolomite resorts are testament to the fact that resorts can offer some very good piste skiing before any large natural snow falls, and can now keep pistes open and in good condition in even pretty dire conditions as long as the temp dips below freezing at night
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pam w,
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Apparently 80% of snow evaporates, rather than melts (can't remember where I read that though).
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For snow to evaporate it must turn into a gas I think this would be difficult without the liquid (melt) phase - it is possible with very low atmospheric pressure - and is known as Sublimation - there that's all I remember form O'level Chemistry..
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You know it makes sense.
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cfc5mu0, well I've sat in a deck chair in the sun and watched the snow steaming. It's turning into very small bits of liquid, I suppose, and thence to the clouds!
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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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OK, I looked it up - quote below from a "science for schools" website.
Sublimation is the conversion between the solid and the gaseous phases of matter, with no intermediate liquid stage. For those of us interested in the water cycle, sublimation is most often used to describe the process of snow and ice changing into water vapor in the air without first melting into water...Sublimation occurs more readily when certain weather conditions are present, such as low relative humidity and dry winds. Sublimation also occurs more at higher altitudes, where the air pressure is less than at lower altitudes. Energy, such as strong sunlight, is also needed.
Source: http://ga.water.usgs.gov/edu/watercyclesublimation.html
The air in the Alps is often really dry (denim jeans will often dry a lot quicker than they do here at sea level) and strong sun is (thankfully) not uncommon.
Snow depth starts dropping the moment it falls - it consolidates, sublimates, whatever. But it disappears at speed, sometimes.
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Poster: A snowHead
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A phenomenon which is visually quite striking off piste is that uncompacted snow disappears quicker than compacted snow. The result is that old ski tracks on old (otherwise unskied) snow, stand up out of the snow instead of being troughs in the snow as you would expect.
Last edited by Poster: A snowHead on Fri 12-12-08 11:28; edited 1 time in total
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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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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I'm having to sublimate my need to ski by writing all this cr*p.
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You need to Login to know who's really who.
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snowball, me too! However, it is interesting, what happens to snow. That effect of tracks (ski tracks and foot prints) standing up out of the snow is particularly noticeable after a couple of days heavy wind/foehn. Let's hope we don't see it for a while.
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