Check out the two glide cracks in The Chimney. photo taken yesterday, 4/6/11.
Knowing that another little storm was coming our way, I was eyeballing the hell outta The Chimney yesterday morning. It’s looking fat, filled in, and lethal. There is an enormous Glide Crack (see definitions below) right where the rocks of The Chimney meet the snow and then another TITANIC glide crack in the upper apron. The first crack is right in the landing of many of the lines up there. I do think it can be aired over in some cases. The second crack, right in the runout, is daunting. It’s 5 feet wide in spots and you’d be doing about 50 mph when you hit the uphill slope of the lower portion of the crack causing your body to instantly vaporize…and it’d ruin your skis, too.
Look at where the lower glide crack touches the huge rock, looker’s left. See how open and frightening that crack is?!
Tomorrow we’ll likely get up on the Palisades and 1 of 2 things are going to happen. 1 = Patrol will recognize the cracks represent manslaughter and keep the Chimney closed. 2 = Patrol will open it and skiers will stand on top scowling into The Chimney for 20 minutes before deciding that it’s no-go.
How The Chimney looked during the most recent Chimney Session on March 28th, 2011.
Well, this is Squaw Valley, so, of course, there’s a third option. 3 = Patrol opens it, Squaw skiers charge the lines and vaporize themselves or somehow pull it off. I’ve seen stranger things.
I can’t tell you how many times, just this season, I’ve looked at a line, said “NO WAY IN HELL”, then watched some other Squaw ski psycho hit it, said “Oh, I guess it’s okay,” then hit it myself. That says something about me, huh? Lemming.
Definition of Glide Crack from The Journal of Geology:
Tensile fractures, called glide cracks, form perpendicular to the ground surface (McClung, 1987) and develop at the crest of an avalanche. During glide-crack formation, rates of snow glide are high (Endo, 1983) and increase downslope from a glide crack, indicating a longitudinal glide gradient (Yamada and others, 1991; McClung and Schaerer, 1993). Glide cracks precede full-depth avalanches, but avalanche release does not always immediately follow glide crack formation.The stability of the snowpack after crack formation depends on interface topography and friction conditions.
Cross section diagram of a glide crack and it’s components. From: Alan Jones
Our Glide Cracks (which are all over the upper mountain right now) are glide cracks that formed from the snowpack gliding downhill and pulling away from snow that was securely fastened near the ridges. We didn’t get avalanches out of our glide cracks…just huge, nasty glide cracks.
The only real solution, albeit temporary, would be to get a massive storm or series of storms with enough snow to plug the cracks. I’m all for that solution, so let’s just do that.