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Every winter we get mugged. Here in Colorado we get snow, oh wonderful fluffy powder. Then the bad guy shows up. A thick avalanche slab hangs there for days, weeks, waiting to kill someone. How do we deal with such “persistent slabs”? We watch slope angles, dig a few pits to see just how tender the slab is, listen to the avalanche forecaster.
We are fortunate here in our HQ town of Carbondale, Colorado that our local ski shop, Cripple Creek, hosts a series of lectures by our area forecaster Blase Reardon. Main takeaways from his recent impartation of wisdom: Persistent slab does EVENTUALLY go away or get buried so deep it’s not dangerous, but the dragon must be watched lest he comes out of his cave while you’re not looking.
Interestingly, a persistent slab can go “dormant” then come alive again with just a small load of new snow. The balance gets tipped, if you will. Perhaps the most important reminder I got from Reardon’s lecture was that persistent slabs are part and parcel to “remote triggering,” that ego destroying encounter with forces of nature when the kiss of your skis or stomp of a boot causes an avalanche to break above you — and take you out if you’re not watching your location.
Where the concept of remote triggering hits home with me is I’m a fan of ski cutting, but a persistent slab can break above you while you’re doing a cut. Thus, ski cutting: Only done on lower consequence slopes preferably _without_ a persistent slab, and use a rope whenever possible. Another thing I’ve been thinking about is how persistent slabs have weak spots often close to exposed rocks or vegetation, but how often have I “skied over by the trees” because I thought doing so kept me out of the main slide danger zone? Imaginary safety based on mythology?
One of our most tragic “remote trigger persistent slab” accidents in Colorado was the 2013 Sheep Creek disaster. Good idea to read up on Sheep Creek, regarding everything from slope angles, to alpha angle, to route finding thoughts. As always, we attempt to cover such accidents in a way that saves lives, through education by example. As always, condolences to the friends and loved ones of those lost. Speaking of which, a shout out to the IAN Fund, a sweet non-profit founded in memory of one of the Sheep Creek victims.
WildSnow.com publisher emeritus and founder Lou (Louis Dawson) has a 50+ years career in climbing, backcountry skiing and ski mountaineering. He was the first person in history to ski down all 54 Colorado 14,000-foot peaks, has authored numerous books about about backcountry skiing, and has skied from the summit of Denali in Alaska, North America’s highest mountain.