How to Read Avalanche Terrain When Route-Finding
Take it from Bruce Tremper: the Utah Avalanche Center’s head forecaster and resident snowpack whisperer has spent more time digging in the snow than some of us have breathing—he’s been at UAC since 1986, worked in Montana and Alaska, and written the definitive book about avalanche safety—so it’s a good bet he knows a thing or two about making good decisions in avalanche terrain. We were able to grab him as he headed out for a ski, and he was gracious enough to crack an egg of knowledge all over our heads; check out the video, read on for some reinforcement, and be safe out there.
There’s no such thing as complete safety when you’re in the mountains, so smart travel in dangerous terrain is all about minimizing risk; read the terrain carefully, choose your route critically, and you’re more likely to make it home in time for dinner. On every trip, you’ll reach what Tremper calls “critical decision spots,” places where you’re presented with multiple options and need to choose carefully—should you skin straight up the gully because it’s easier going, or stay on the ridge?
Before you opt for the gully, think about the consequences: it’s what’s called a “terrain trap,” meaning that even a small avalanche can be catastrophic there. If you stay on the ridge, an avalanche is more likely to spread out underneath you, giving you a better chance of avoiding getting caught altogether. Whenever you’re moving, keep an eye out for terrain traps and other features like cliffs or trees that, if you got caught, could turn a small avalanche into a serious disaster.
It’s also vital to know the steepness of the slope you’re thinking about hitting, as well as its direction, or aspect. Almost all avalanches happen on slopes between roughly 30 and 45 degrees, which also happens to be prime ski terrain; steeper slopes tend to regulate themselves more efficiently, while shallower pitches generally don’t have the requisite energy for a major slide to occur. Before you head out, it’s a great idea to pick up an inclinometer, which is cheap, small, and will help you easily tell how steep a slope is before you get on it.
Aspect’s another key piece in the avalanche puzzle. From early to midwinter, north- through east-facing slopes tend to be the most dangerous, while southern and westerly pitches become susceptible to wet slides in the spring, when temperatures rise and they get more direct sunlight. Most avalanche forecasts feature what’s called a “danger rose,” a modified compass that displays aspect, elevation, and corresponding danger ratings, letting you quickly see which slopes are best to avoid and which offer the safest bets for the day.
So read your local avy forecast every morning with your coffee, take a certified avalanche class before you start spending time in dangerous terrain, and always focus on travelling safely and minimizing risk; there aren’t any guarantees out there, but there’s a lot you can do to make it home in one piece.