Turning on the brain : Few questions.
So again it starts to be the time of the season that the avalanche books appear on the night stand and thinking of snow
kicks into the high gear.
Been mulling around with couple of questions,especially about the hakuba area / snowpack.
So,I am here just thinking aloud,in general terms and stuff so bear with me.
First.
Early season snowpack stability : That japan area is in that sense quite unfamiliar with me. Very few places (maybe in alaska and norway) get the early season dumps as big (0.5m-1m+) as japan. Maybe on top of small amount of previous snow or even on top of snowless ground.
In broad and general terms, how stable is that snowpack during the first couple of days and what kind of history is usually expected from a thick base layer? Say,compared to a multiple layer,weather affected,progressively grown snowpack?
With a long hard dump (?!) the snowpack is usually quite isothermal and homogenous, it usually lack very distinct layers (no surface hoar) and within the first few days the developement of depthoar due the warm ground is slow?
Second.
Snowjapan´s Hakuba now avalanche hazard ratings : By a quick browsing it seems that hakuba area has a moderate(3),high(4) or extreme(5) avalanche hazard on about 80% of the season. How is that possible? I mean, most maritime areas (like that said norway wich I have most personal experience off) have few high hazard days during or couple of days after the big storms but generally stabilize very quickly. Of course they have crust/hoar layers that might be present for longer periods, but on very broad general terms, the avalanche hazard seems to be way lower during the season.
Does this come down to : different categorizastion in hakuba area (by the forecaster), a mixed climate (maritime+continental) or weir combination of whatnot?
Threeded.
Have you guys followed ,or might some one of you be intrested following this weather site : http://www.wetterzentrale.de/topkarten/fsavnoas.html during the season to see how the predictions hold during the season?
Just that for me personally this has been the most accurate forecasting service. Been using it in south america,NA (canada), northern europe and southern europe. Comments?
Disclaimer :I havent fully woken up yet and not a avy forecaster so bare with my ramblings. Just trying to prevent a shitfest that many avy threads seem to become..
Cheers!
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Here is what I just posted in reply to your same Q on TGR.
I'm not speaking from years of local experience here.
Firstly, you might like to read my avalanche review of last season on my blog:
http://steepdeepjapan.com/avalanche/0708-summary
If you want to follow the snowpack then follow my blog come winter. I collect profile data for the Japan Avalanche Network (JAN) nearly every day and blog a summary of what i saw each evening. I'll be cross posting in on poachninja.com this season as well. The JAN database is a little like the CAA Infox service for member guiding operations in Canada, except that the JAN data is online for public viewing. Every day you will find hazard assessment in accordance with CAA methods. Its written in Japanese but once you know where to look you can check it every day. On one day you often get a hazard rating for various locations across the valley.
Early season snow dumps of 50-100cm usually fall on a lot of bush and high scrub/giant grass etc. Its enough to squash some of it, but there is no energy or support in the base. You might find ok stability, dunno, wait and see. In the alpine the snowpack is stratified and wind affected well before any big storms deliver 100cm below the treeline. Last year most of the below treeline base formed in two big dumps like you mentioned. It was all intertwined with the vegetation and that might have held it in place a bit better. Compared to what I saw in Europe, the treeline pack here in Hakuba starts out thick and warm and is possibly more stable than a pack whose early season base is formed of several small colder storms. Even if the treeline base here was made up of unstable layers from early season, its usually 3 meter down by Jan so can be largely forgotten.
Mate, forget Snow Japan - that is not their report they just have permission to use it. It comes from a local guiding service (Evergreen), even though Snow Japan wont credit them as the source with a link - yet expects people to trust it without even knowing who wrote it. Snow Japan has nothing directly to do with avalanche safety in Japan, forget them.. The report is originally published each day here on Evergreen's blog http://japantours.evergreen-hakuba.com/ Get it from the source and contact them direct for any questions. In general and to answer your questions as best I can:
- it is not fully fledged avalanche forecasting service - no such thing exists in Japan. The guy who writes it is a CAA instructor, he is not a hack.
- They are probably biased to being conservative since it is not their duty nor obligation to publicly state every day how safe the snowpack is.
- We do have a maritime pack, but it blows a lot in the alpine and at tree line. There is heaps of snow transport, every other day you get more significant transport. It also snows almost every 36 hours here, and almost always more than 20-30cm above tree line. As soon as our maritime pack settles, another less stable mix is added to the surface, often upside down snow (starts cold, ends warm). Sadly rare are the extended periods of blue weather for the pack to settle. Winter kind of sucks here in that regard.
- I am a hack, but agreed with most of their ratings last season, although sometimes it didn't change to a lower level as fast as conditions perhaps said it should.
- Keep in mind who it is written for: people who have probably never even read a CAA or European avalanche bulletin and really do not know what 'moderate' means. I would hate to write an English forecast for the typical western skier in Japan.
- 15km up the valley and you can have a very different pack - without a locally specific it would be hard to forecast without erring towards caution.
Never seen that weather site, I will take a look over time.
Hi Meathelmet
Your weather link (http://www.wetterzentrale.de/topkarten/fsavnoas.html) gives similar charts as the Unisys site that I'm sure a lot of ninjas have used in the past. The East Asia charts at Unisys have not been displaying recently for some reason, so your link is a great help.
For those who've not used it, the 850 mb/hPa chart gives you an idea of temps at mid mountain (1500m or so) in Hakuba. In the wetterzentrale site, green is sub zero, which is maybe a little confusing at first.
For people slow on the uptake, the usual disclaimer applies about the long range forecasts.
Yes, I noticed the 850 GSF plot went blank a while ago. I have it embedded here: http://steepdeepjapan.com/weather/850mb-plot
(Should get Admin to embed it at PN when it comes back to life). In the meantime MH's link is very helpful.
For those that do not sprech German, you want to select Ostasien in the green menu on the upper left. Then 850hPa temperatur 9 panel in the grey area at the top. http://www.wetterzentrale.de/topkarten/fsavnoas.html