 Poster: A snowHead
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| andy from embsay wrote: |
| @VolklAttivaS5, the cannons in Avoriaz were going like stink before Christmas- they closed quite a few runs because the piles of artificial were so big they blocked the track. |
That’s good they used them.
It has been too warm this last week or so to have them on admittedly.
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@VolklAttivaS5, in fairness, it isn’t cold enough to run cannons
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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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@under a new name, yeah ^^
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@VolklAttivaS5,
Allegedly a few of the Austrian areas were running their guns 24/7 to make as much snow as possible up until 1st Jan when their elec contracts were due to more than double in cost, after that date used very sparingly.
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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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@alasdair.graham, ah I see well that would make sense
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Well the latest Avoriaz1800 Instagram story is slightly encouraging. Actual snow falling!
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@VolklAttivaS5,
But you are right they do seem to do very well with getting everything going in that part of the Alps early doors each winter.
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@alasdair.graham, it’s true it’s well organised
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You'll get to see more forums and be part of the best ski club on the net.
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| kinger123 wrote: |
| Well the latest Avoriaz1800 Instagram story is slightly encouraging. Actual snow falling! |
Maquillage, as they say in these parts.
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We were up Fornet / Grande Conche yesterday morning - there was about 20cm fresh up top. Situation below 1700 was pretty dire with a lot of new bare patches. Runs down to Lindarets now limited and with all the traffic from Morzine and Les Gets in Avoriaz, what's left is incredibly busy and getting moguled rapidly. The pistes that are open were littered with folks who were clearly struggling!
Fornet was much quieter, poor viz but managed some fresh tracks before 10am, so it's not all bad 
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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| under a new name wrote: |
| @davidof, hmmm, I was reading somewhere that cannons are reasonably efficient (who knows for what values) and don't use so much power. Who knows? Anyone? Bueller? |
One of our sons did a work placement with the Pleney piste team, and along with fun things like getting to drive a piste basher, being towed fast behind a skidoo and keeping the rescue dogs entertained, he did quite a lot of work with the snow cannons.
I do not remember all the details he told me, but from what I remember ...
They are pretty efficient, especially the 5m lance type. A few years back a decision was made to go from a few big fan blower high volume cannons to the smaller lance type, because it takes a lot of energy (pistebashers) to redistribute the massive mounds created by the high volume blowers, in comparison having 3/4 lances produces similar amount of snow for the same cost, but is much cheaper to use as it does not need spreading out as much.
The cannons operate from -4 downwards, and hit their most efficient at -8.
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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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@OuatteDePhoque, have they stopped using the additive that let them run from about 0C downwards then?
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@under a new name, My son was there 5 years ago, and they were not using the additive at the time, but thats not to say they do not use it now.
Theres 4 lots of holes on the lances. The bottom holes feed pressurised air, then each of the next 3 sets of holes feeds water into the mixture. At -4 the 2nd holes allow water in, then at -6 the next set of holes open, and at -8 and beyond the 3rd set opens, giving you maximum output. So the volume of snow produced increases inversely with temperature.
In terms of efficiency, the colder the better. Maybe if your'e on the hill today in Cham, have a gander at the cannons and see how many of the holes are blowing snow, then look again on a warmer / colder day.
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You know it makes sense.
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@OuatteDePhoque, when I last heard about using additives it was a lot longer ago than 5 years. I can easily see that it might not be too eco.
I think I am not so fascinated
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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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Pretty sure the use of additives was banned ten or fifteen years ago.
Ambient air temperature is not the only limitation on use of snow cannons - the water temperature also plays a large part, and that in itself is affected by how much it has to be pumped to get to the delivery area. For example, the snowmaking facilities in les Crosets which are fed from a reservoir at 1800, can operate at a couple of degrees higher air temp than those at Follieuse, which pump water from the river at Morgins village level (1300m).
I believe that different designs of snow cannon have different temperature limitations as well.
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Poster: A snowHead
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@Chaletbeauroc, Maybe thats why the 'torrent' in Morgins has sod all water in it.
TBH I'd have though the lac in the Pas would have been a better source.
Also because its higher, it will already have sufficient pressure to get 1/2 way up the Bec de Corbeau, whereas you'd need stronger pumps to bring it up from the river - where in the river do they extract it? Is it up behind Rafaiasenbank ?
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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@OuatteDePhoque, Sod all water? You haven't seen it in the last couple of weeks, have you? They were actually unable to run the Morgins snowmaking because the river was so full, including a lot of mud and debris. I'm not sure exactly where they take it from, but probably up where the central heating building is, a bit further up from the ATM.
The point about the pressure is relevant to the temperature. The more you need to pump it, the greater the rise in temperature. To use water from the lac de Morgins to take advantage of that would require a completely sealed system all the way down to the village, the cost of which I imagine would be punitive, but in any case there isn't much of a flow into the lake, such that half of the area is marshland for most of the year anyway, so it's pretty much a non-starter.
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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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Caught the BBC snow conditions update that said no significant snow was on the horizon for the alps? There are too many sources of misinformation / bias and lazy reporting around so best to do your own research.
One of the easiest ways to judge the FL within a week or so is via the ensemble graphs. On wetterzentrale you only have the 850hpa (1500m) temps to look at, and flicking between the 4 models you can see that ECM and GFS show average temps (white line) dipping below 0c monday into tuesday. The other 2 models GEM and ICON only show the average line just glancing the 0c level. Also note where the Op (green) and Control (blue) lines go....you want to see these below the mean ideally (and they are on the latest runs, 0z). So putting all of that together there I'd still say about 70-80% chance of snow to the valley floor (1000m).....but it won't make much difference to opening the whole area if snow at 1000m gets washed away or isn't deep enough.
https://www.wetterzentrale.de/en/show_diagrams.php?model=gfs&var=2&geoid=43270&lid=ENS&bw=1
A look at todays 06z GFS run shows the FL could be close 1200m even on Sunday morning (8th), but I think odds favour a slower progression, so monday morning is more likely.
And by Tuesday morning, there is a chance of the snowline getting down to 400-500m, which would be nice, but not important if it doesn't get there.
Bearing in mind the above output is just one Op run, the mean temp graph is also worth looking at, and here its showing the average ensemble temp level at 1500m is below 0c on monday morning. So it should be snowing at 1200m by then.
Using the meteociel diagrammes is even better as they allow you to switch from 850hpa temps to ISO, which is the freeze level. Middle section at the bottom has the various viewing options. Here's the 00z, and you can see the mean (red) FL is about 1200m from the 8-10th. It climbs up towards 2000m on the 11th, but precipitation will have faded to insignificant amounts by then. Further out into mid month there is a continuing signal for colder conditions again, with 1500m temps averaging 0c, so very much seasonal for mid Jan. Still scope for some nice top ups as NW flow remains an ongoing possibility.
Click on top right link 'Diagramme ENS. GFS', and can easily change resort at the bottom of the page, but won't be significant differences across PdS.
https://www.meteociel.fr/previsions-neige/27685/les_gets.htm
Then at the bottom of the meteociel ensemble page you can switch the 850 temps to ISO, which is the freeze level, shown below.
One other source I use is meteologix. Similar to above but with more models to view. Not all of them offer FL, so best to select 850hpa for easy comparison. Select the date bottom left. By Monday morning most of the models are below 0c, although a bit concerning that UKMO is still positive. It's one of the most accurate models so we need to see that model come on board very soon. However by monday evening all models are showing negative values. Note you have to select a long range model like GFS to change the dates further out as some models are short range.
https://meteologix.com/fr/model-charts/deu-hd/france/temperature-850hpa/20230109-0600z.html
Finally once we get into the 2-3 day range (from friday) I use the meteociel previsions link above that will allow you to view freeze levels from GFS, WRF, Arome and Arpege. Of these I think WRF is the most reliable. GFS can be too progressive, Arome too conservative.
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You need to Login to know who's really who.
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Thanks for taking the time to provide such detailed info @polo. I understand little of it  , but it sounds encouraging even if subject to change. We're out on the Fri 13th with first day skiing on the Saturday so currently obsessively looking at snow reports and keeping everything crossed.
If there is decent snowfall over Sun/Mon/Tues, would it likely be enough to get resorts fully up and running and have snow covered valleys?
Last edited by You need to Login to know who's really who. on Wed 4-01-23 12:15; 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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@polo, you're an absolute legend for taking the time to detail all of this in such a clear, objective and eloquent manner. Thanks.
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@polo, This is really above the call of duty Polo - thank you so much
Like others, we're out on the 14th for 2 weeks and are frantically waiting on your every word!
It does look like the entire alps are about to get a pounding for 3 days or so - glad we're not travelling right in the middle of it
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@kinger123, allow me to simplify, it will snow next week, anywhere from 20-50cm, mostly above 1500m, but also well below.
Yes I can't see why most of the area won't be open by end of the week, and the valleys will be white again.
Re. above, it's a hobby of mine I can't shake.....so might as well share some insights, especially in desperate times like these.....although I get plenty of snow sliding in every season I still want to win all the forecasting 
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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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@polo, I've noticed that too. Is there a shift in expected pressure gradients that's causing the reduction? Also, which direction is Sunday-Tuesday's snowfall coming from - is it southwest / west / northwest?
Looks like Morzine's single remaining open slope (Piste B) may have finally succumbed to the thaw today.  Mind you, they did well to keep it open that long.
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snowHeads are a friendly bunch.
snowHeads are a friendly bunch.
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Another mention for @polo in despatches. Thanks and do please keep it coming. Cheers.
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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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@polo, same, great work and explanations. I'm off to Grand Massif (Samoens) on 13th so keep an eye on both threads as both areas seem to be getting similar weather hits this year. Do you think your predictions stand for over there too?
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From doing seasons in the Tarentaise (5), I hate to be a killjoy re weather/snow predictions, but unless we had a stable high sitting overhead you could never trust the weather forecast beyond 48hrs.
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You know it makes sense.
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This isn’t just any weather forecast, @Kenzie, it’s the @polo, weather forecast…
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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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I don’t know who was calling 20cm yesterday morning (earlier in the thread) but that was a tad optimistic! There was fresh about about 1800 but it had rained to all levels before turning to snow from about 1800m upwards.
Some nice skiing about early today but very, very icy in spots and absolutely rammed. Ardent parked both sides of the road down to the first tunnel. Lots of accidents about too and almost constant helicopter noise this afternoon.
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Poster: A snowHead
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@Kenzie, you are right, and some set ups like this one are more risky than others.....I said it was knife edge stuff because high pressure is so close and the angle of approaching low is too westerly for comfort.
@denfinella, yep the high fills in quickly on monday behind the westerly low, which is drifting and splitting more NE than before.
@dunc999, at this range it's all rough numbers so GM should look more or less the same
I see wepowder.com have similar thoughts / suitably cautious. We'll find out soon enough
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Obviously A snowHead isn't a real person
Obviously A snowHead isn't a real person
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| Quote: |
| @Chaletbeauroc Sod all water? You haven't seen it in the last couple of weeks, have you? |
I drove thru twice on Thursday on my way to Verbier and back, but I did not take the time to stop and admire the watercourse as in the morning it was dark and in the evening it was peeing down
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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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Steady output on the 12z, better from UKMO, less so GEM re. temps getting below 0c....no real change to above, except Friday 13th is now building nicely.....might just be one mild dry day midweek before a second trough rolls in from a more NW direction thurs-fri...shown here on ECM, but also supported by GFS mean
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I normally only get fanatical about the weather in early season, up until the point that a base is down to low levels. But as this is base build 2.0 and we are still suffering autumnal weather it's got my attention for another few days.....
First let's get the poor output out of the way, JMA and GEM keep the flow westerly into next week and as a result the 850 temps don't really get below 0c.
The better news is that ICON, GFS and UKMO all show the trough digging further SE, with more of a NW tilt to the air source. ECM is somewhat of half way house, but still has enough tilt for sub zero temps in our area. ICON below for comparison to GEM above.
GFS is still keen to bring in the cold on sunday afternoon, with FL potentially 1200m by evening. This would be the best case I think as the first heavy band of precip crosses on Sunday, so the quicker the temps drop the more snow / less rain lower down obviously.
By monday morning GFS is sticking with a sub 1000 FL, possible snowline down to lac Leman. I wouldn't put much money on it, but if it comes off then it just means slightly tougher driving conditions and better quality snow on lower pistes.
Later in the week is still looking like a reload on thurs/fri, here's the ECM mean. It has been well forecasted for a while now that out to the 15th had further potential based on several models showing low anomalies over europe. Not nailed on yet as again GEM is dragging it's heals, but so far so good.
Precipitation is more hit and miss even within 48hours....last night was probably heavier than expected albeit with a 2000+ FL.
ECM and GFS are predicting up to 50cm by Friday, other models total precip can be viewed here for the Rhone Alps.....lots of pretty colours
https://meteologix.com/fr/model-charts/swiss-mrf/haute-savoie/accumulated-precipitation/20230113-1800z.html
Summing up
Sunday afternoon should see the first showers, probably close to 1800m snowline but droping steadily into the evening.
Monday morning the valleys will be white.
Tuesday will be awesome.....remains to be seen how quickly they can open the area.
Wednesday will be mild and dry.....no rain expected
Thurs-Sat temps drop back to normal again, FL around 1500-1600m intially, more snow likely
Last edited by You need to Login to know who's really who. on Thu 5-01-23 10:36; 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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This is amazing research - thanks @polo.
"[R]emains to be seen how quickly they can open the area" there are clubs and local schools coming for Wed afternoon, hopefully the SAGETS wants to keep those happy.
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@polo, Thank you once again - wonderful news for our arrival on the 14th - you're a legend!
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@polo, great stuff thanks. Looks like not much is going to arrive in time for our departure on Monday night, but tbh I just want the Cloggies to go home so we can access what there is up high without queueing. Then a decent base before we’re back again at the end of Jan.
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| Quote: |
Thank you once again - wonderful news for our arrival on the 14th - you're a legend!
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A legend, he would still be, even if the outlook had been worse. Sometimes in this thread the people who have taken the trouble to explain to the rest of us what might be happening have been subject to a fair bit of abuse for being "pessimistic" when what they have been is analytical and objective. Having such a detailed look (not just cherry picking the best of the model ensembles) helps underline what an imprecise science it still is, despite the mega data. Quantities of precipitation are particularly difficult but people only remember (and moan) when the skies deliver less snow (or more rain) than their fave website (such as snow-forecast) appeared to promise.
We should also remember to thank our weather gurus when they tell us it's going to be grim, and it is.
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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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@pam w, not seen any abuse on this thread. Anyway, even though I always strive for the truth, good or bad, I am just a glorified copy-paster. I like charts and spotting trends, very ordinary stuff really. But great if I can help share my limited knowledge with a wider group.
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@pam w, A very good point indeed - I guess its just human nature isn't it - we always remember the good stuff
So for now, Polo is in our good books he he he!
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FAQ
thanks for that, hopefully I'll sleep a little easier with the prospect of snow!