Avalanche
Bias, Variance and Loss in Avalanche Forecasting by Peter Donner Revised: April 9, 2019 Statistical theory is relevant to avalanche forecasting through the concepts of bias, variance, and loss. Bias is the systematic difference between the forecast and actual conditions. Variance is the random difference and captures the notion that
Avalanche
A few years ago, one of my best friends was caught in an avalanche somewhere north of here. The avalanche was triggered from above - another skier on the slope - and as the Leviathan roared down, he pushed another skier out of the way toward safety...and suffered the
Avalanche
Originally published in this winter's hardcopy issue of Ascent, the Backcountry Snow Journal Not long ago, I heard a story from an old colleague of mine. It was his first year as an avalanche professional and he was out in the field with his supervisor. The two of
Avalanche
From Ed LaChapelle's essay The Ascending Spiral in The Avalanche Review 24.1 (photo credit -Wilburn and Jean Pickett Photograph Collection, University of Utah Marriott library archives) “Do nothing in haste”......this speaks loud and clear to the pressures of time, planning and economics, plus the perpetual urge
Avalanche
A few people have suggested that I condense my Utah Snow and Avalanche Workshop/International Snow Science Workshop presentation into an article. There are very few well-documented cases of dry snow avalanches being triggered by solar radiation and/or warming. (cover photo: Todd Glew - Gobber's Knob, Big
Avalanche
In his seminal book The Hunters or the Hunted, the celebrated anthropologist Charles Kimberlin "Bob" Brain postulated that it was our relationship to monsters that established us as we are today. As a native of Tasmania, Brain wrote not about a whirling devil, so to speak, but of
Avalanche
Chris Cawley, Alta Ski Patrolman and frequent backcountry observer, recently shared a great link from NPR about "free will" with decision making...that, according to author Sam Harris, "our brains decide a course of action before we know about it". I thinking about it, it may
Meditations
I AM Dangerous A couple of summers ago, Steve Markusen was found high on the Exum Ridge of the Grand Teton. Bloody, staggering, disoriented and solo, he asked the party of three who found him where he was. Hours later, Jenny Lake ranger Nick Armitage flew in beneath the rescue
Avalanche
Two winters ago, a party of self-described expert skiers and snowboarders exited a ski area to center punch a very steep and committing untracked bowl of almost-thigh-deep powder. It was bluebird, and the stoke was high. Most of the party had been through a Level 1 avalanche class; they had
Meditations
Take any owl feather and whip it through the air. Know the sound it makes? It makes no sound. This is not the sound of a raven’s wing. The Trickster has a deep, low beating sound of feather against air; a “whoop whoop whoop” that can often be heard
Avalanche
Six people are deeply buried in an avalanche in the Wilson Glade. One is caught but holds onto a tree, safe but not sound. Three of the six burials are from a completely independent party, strangers he never knew but soon will. He acquires the first signal, digs and gives