Dying For Powder

Sometimes you hear a crack or a roar. More often the first sign is snow shifting around your feet. The snow starts in a slab and then breaks into blocks that knock you off your skis, careening down in a slide moving as fast as 60-80 mph. If you’re lucky, you live through it, plastered with snow; if not, you’re entombed, hurtled over a cliff, killed.

There have been 36 avalanche fatalities in the United States this winter, a streak of avalanche deaths not seen since 1918.

The accidents all occurred at a time when forecasters had rated the avalanche danger considerable or high. Both ratings mean...