View Full Version : Spring snow, and such
03-08-2005, 12:36 AM
Noticed some natural avelanche activity today in places that I've never seen slide. I figure this had something to do with the freeze thaw cycle heating up (literally). Now I want to ski at some point this week but am kind of scared. What should I look for in pits asides from layers in the snow? Reading the eaglecrest avy report it seemed that isothermal snow is fairly safe if its supported somewhere. Is this correct? I'm definately staying below 30° untill things are isothermal or things freeze.
03-08-2005, 08:10 AM
i suspect that these are wetslabs you are dealing with, which can and will slide on lower slope angles. when a snowpack first becomes isothermal it has a problem getting rid of all the melt water it produces. the water builds up on the first real impedence layer (crust) and lubs it up. the water basically floats the slab up and degrades the bonds between the crystals until it releases. after a week or so of becoming isothermal you should start to see drainage channels formed within the snowpack. this allows the water to percolate all the way down to the ground. if the ground is a smooth grass slope or slick rock, you could start to see glide.
in short, start early and end early. work your aspects so that you are getting off of them as the sun turns them to mank. start with the east and work your way to the west aspects. if you are sinking in past your ankles then it's time to move.
edit to add that heating will cause the persistent weak layers even on the shady slopes to become more active. you should be able to notice that with simple pit tests.
03-08-2005, 07:47 PM
the avy I observed definatley had a snow bed surface, I suspect it was the first layer of snow for the season that turned very solid, thne we had sugar and crust. Good info APD hopefully i can keep from killing myself :)
03-08-2005, 08:04 PM
how deep was the crown? it was likely one of the last crust layers deposited that went. look at the bedsurface to see if there are any striations. those are almost always present in wet slides.
look at the debris in this one. kind of manky and cohesive looking. you can also see some of the striations in this pic. this pic is from yesterday at 3:30pm on an east aspect.
03-10-2005, 09:08 PM
crown looked to be a foot or two, obvious place for an avy what with the amount of cross wind loading.
03-13-2005, 01:08 AM
as far as terraine goes except for slope angle its very obious, its low angle though. There was a class 2 (i'd guess) avy on a line that I wanted to ski this year 2 days ago definately waiting for my beacon to come in and things to settle down. I'm thinking of waiting untill may do do it and go way early in the morning (like sunrise so 4:30 AM) hmmm i think I just planned a perfect walk of shame for after prom
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