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Recently, at higher latitudes, summers arrive from of winter with more intensity ( see this http://www.bbc.co.uk/news/science-environment-15105747 recent article on ozone for recent patterns) , and the winters are becoming more intense and cold.
How is avalanche prediction changing along with the weather, or is there more data to acquire?
Way too soon to tell or have any hard facts. Probably not in my lifetime, nor yours.Quote:
Originally Posted by DasBlunt
Dust on snow events are becoming more common in some places with all the issues that a fucking dirt layer brings.
Hey DasBlunt, you probably want a technical answer, so I'll write one. For clarity's sake, I'll include information you probably know.
Backcountry avalanche forecasting is concerned with the spatial and temporal distribution of instability at a specific place and time.
Office-based forecasting is concerned with the spatial and temporal distribution of instability over an entire winter, and possibly other winters.
The character of a specific winter does not change the methods used to align your perception of instability with reality.
The Avalanche Handbook says that climate is only applicable to forecasting in an extremely rough, general sense.
Snow climate ( continentality ) is more applicable than general climate, but it doesn't actually tell you anything specific about instability.
Spatial scales for avalanche forecasting: synoptic, meso, micro.
Temporal scales for avalanche forecasting: this winter, this month, this week, right now.
Historical records of avalanches are very thin over most of the world. When you combine non-existent records with the chaotic ( in the mathematical sense ) nature of the weather, it becomes clear that even if there is a relationship between climate change and avalanches, it'll be pretty hard, if not impossible, for anyone to sort out.
Longer, cooler winters might have higher overall instability which is certainly of interest to avalanche forecasters and recreational skiers alike, but the character of a particular winter isn't really applicable to go/no go decisions for a specific place and time.
Some interesting(?) data on Rogers Pass:
http://nparc.cisti-icist.nrc-cnrc.gc...doc&an=5329123
This is one of my favourites:
http://www.nrc-cnrc.gc.ca/obj/irc/do.../nrcc19020.pdf
The second link will probably give you some very good answers to your questions. Page 64 has a really neat map of all the avalanche paths from Albert Canyon to Stoney Creek. Toward the end there are diagrams of synoptic scale weather systems discussed in the paper.
Found this:
http://www.realclimate.org/index.php...ky-is-falling/
Not sure what effect UV has on snowpack stability but gut intuition says that if the climate is getting warmer and wetter than there will be more snowfall (presuming it doesn't get too warm and most of the precip still falls as snow). so bigger snow storms = bigger avalanches.
Thanks. The recent Russian example had me thinking and you answered my questions.Quote:
Originally Posted by CookieMonster
You quote above is perfect. A question though, based on the fact that summer is arriving so fast lately, and if we get deeper freezes with faster thaws, is there any part of avy prediction that would change? Are there new observable variables being created in the snowpack based on the proven recent rapid warming?
Thanks for the kind words. I'll try to answer your question below. There are not new observable variables being created because the laws of physics ( at this level ) are very consistent.Quote:
Originally Posted by DasBlunt
Take the two trends you mentioned:
A. Warming
B. Cooling
Now, take three scales of time.
A. Right now.
B. This week.
C. This winter.
Now, given the consistency of the laws of physics, we can make a matrix ( in the form of a list ):
1. Warming right now.
2. Cooling right now.
3. Warming this week.
4. Cooling this week.
5. Warming this winter.
6. Cooling this winter.
Now, you can easily make some predictions for what will happen with the snowpack.
**
I wrote a blog post about warming/cooling and the scales of time. There is a table at the bottom of the post that attempts to clarify how warming, cooling, ( and loading ) can increase or decrease stability based on the scale of time over which the trend occurs.
( This is germane to your question since you're asking about how climate-driven trends over an entire winter might affect avalanche forecasting. My point: instability isn't related to climate, it's related to physics. )
http://avalanchesafety.blogspot.com/...intaining.html
Well, from a recreational skier/boarder's perspective, the most important facet is when that slab will actually give way, which is determined by a large dataset of local variables...said variables to be quantified during that specific time interval....not next season or the season after.
What you're talking about (long-term temperature differentials and their effects on localized environments) should not have huge affect on route-planning, as route-planning should be done on a day-to-day basis. During any season, there are often large temperature and dewpoint humidity fluctuations in a local area...these individual fluctuations will affect snow physical structure at various points (think of a core analysis).
Now, whether there are increased average temperatures in a localized area over a 20 - 75 year period should not quantitatively change one's method of slab stability analysis, as such analysis should be based more upon that month/weeks/day's data for specific physical stability rather than a non-quantitative forecast of 'possible' slab stability parameters based upon a historical limited variable dataset.
So. in other words, your interpretation of your slab-testing for a given route should be based categorically on observable data and less on mathematical modeling.
Now, over a long period of time, where there may indeed be substantial warmings and coolings affecting snow layers, then stability aberrations will become more evident...but whether they will necessarily be causal to increased or decreased stability would take a very large data set to determine.
I think in the field, where safety is at stake, quantitative analysis should take a back seat to inferential analysis based upon local experience, pole-probing AND gut-feeling.
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