You May Never Have Heard of Ski Slopes' 'Silent Killer'

You know that trees can be deadly for skiers and snowboarders if they lose control and slam into the trunk. But what you may not know is that the innocent-looking depression in the snow that appears around the base of a tree after a lot of snow falls is, in the words of the San Francisco Chronicle, "the silent killer of the slopes." These so-called "tree wells" are "quicksand-like funnels" that form when the bottom branches of an evergreen catch snow; snow tapers down to the base of the tree and the above-mentioned depression is sometimes hidden by the lowest branches. If you fall into one while skiing or snowboarding, it will likely be headfirst—and the edges easily collapse, trapping you. Trying to get out usually just causes you to be buried deeper, and others may not see or hear you. The past month has seen stories of people dying in tree wells at Oregon's Mt. Bachelor and Mount Hood, as well as the Lake Tahoe region.

In a single week last year, at least seven people died of what's officially called "snow immersion suffocation" in western North American tree wells; they kill, on average, around as many people as avalanches do every year. How to avoid them? You could avoid slopes with lots of trees on big powder days. The Tahoe Daily Tribune notes that the deeper the snow, the bigger risk of getting buried in a tree well. Using the buddy system, wearing bright clothing, and having the number for ski patrol saved in your phone are other good practices, or bringing along a beacon, probes, and shovels if you know you're going to a dangerous area. It's also recommended that skiers keep their hands free of their pole straps so that their arms don't get trapped if they do go into a tree well and can then be used to at least dig out a breathing space. (A young cadet died skiing. Now, a "bittersweet result.")