tag:blogger.com,1999:blog-815565305562111401.post3332088941305555431..comments2023-10-29T03:14:22.828-06:00Comments on ton of fun: snow procbmhttp://www.blogger.com/profile/06731897972087480687noreply@blogger.comBlogger1125tag:blogger.com,1999:blog-815565305562111401.post-72155248384339993982009-12-19T00:18:02.531-07:002009-12-19T00:18:02.531-07:00Ok, you asked for it, here I go...
Chances are th...Ok, you asked for it, here I go...<br /><br />Chances are the well established ice lens is trapping moisture being moved vertically through the snowpack by pressure gradient... Once the vapor reaches the buried ice lens, it is trapped creating a warm, vapor saturated environment and large T gradient between the ice lens and snow interfaced immediately beneath it... These conditions can produce well defined facets with very poor cohesive properties immediately adjacent to the ice lens... IF you care, technically the process is called "Kinetic Metamorphism."<br /><br />The bonding on top of the ice lens must be of better quality... It is possible that where you were for your second stability test (probably right next to the first test- welcome to spatial variability), snow that fell on top of the lens had minimal T gradient between it and the ice lens and bonded better than the snow that is decomposing beneath it... It would be my guess decomposition is not taking place on this interface because the snowpack environment is not vapor saturated and the T gradient remains within the confines of destructive metamorphism (rounding)...<br /><br />Oh, the "settlement" you are referring to is probably related to the piss poor quality snow (facets) beneath the ice lens... AND, it's actually is NOT settlement... <br /><br />The noise and sometimes movement you feel is "catastrophic failure- aka "Whumping...” Technically, this is failure occurring at a weak layer/ slab interface at greater than 20 m/s...) <br /><br />The reason it didn't avalanche is probably because you were either in the right place (lots of anchors and/or in low angle terrain) or there was not enough energy stored at the interface of the slab/ weak layer interface. <br /><br />Don't you worry, whenever I am surprised by a "Whump” I say "Did you feel that F'n SETTLEMENT! <br /><br />Ok, now with all that said, I would once again like to pitch my safety message and say if you are headed into the backcountry to recreate this weekend or in the near future, be conservative, have a solid partner, have a plan, know your line, and escape options if things go bad. <br /><br />REMEMBER, expose only one at a time and make frick'n sure you and your party ARE DIALED IN with proper rescue gear and technique.<br /><br />Have a safe weekend!!<br /><br />Ted Steiner.Ted Steinerhttps://www.blogger.com/profile/01865615167893947474noreply@blogger.com