In this episode of Dynafit Field Notes, Rob Hess shares a few useful tips to help you flow through the mountains and make clear decisions in the backcountry.
Sean Zimmerman-Wall is a full-time ski patrolman at Snowbird, an avalanche educator, and an Andean mountain guide. Check in on Tuesdays for resources and education that will help you have a safe and good season exploring terrain beyond the boundary line. Homepage photo: Ian Coble
Snowpack, weather, and terrain—those are the three points of the avalanche triangle, and we’re in the center of it. We can’t control how much it snows, whether the wind blows, or how steep the terrain is. But we can control where we go. Planning a backcountry tour requires an intimate understanding of the factors that affect terrain and how to manage them. Here’s an overview of a few things to think about when you choose what to ski and when.
Slope Angle: When you consider terrain, think about what you want to ski and what you will be traveling through. The magic number for avalanches is 38 degrees. That’s about as steep as a double black diamond trail at a resort. Slopes less than 30 degrees generally aren’t steep enough to slide, and slopes greater the 50 degrees often shed snow naturally before it can become much of a hazard. If it is steep enough to have fun, it is steep enough to slide.
Slope Aspect: Which way does the slope face? In the Northern Hemisphere, slopes that face north and east usually have the deepest and most complex snowpack. Slopes that face south and west generally have a shallower snowpack that features crusts from sun exposure. Ski the southern exposures in the morning and the northern exposures in the afternoon.
Elevation: Lower elevations often have a shallower snowpack which means that trigger points are easily found. Middle elevations around treeline offer a mixed bag of conditions but can be great skiing on high hazard days. Upper elevations above treeline are exposed to all of the elements and can see a deeper snowpack, more wind loading, and overall larger slide paths.
Terrain Anatomy: Think about the landscape you’re heading into. Are there anchors, or islands of safety? Large, dense, old growth forest is usually a good sign that you aren’t in a major avalanche path. Although small pockets of dangerous instability still exist in forested terrain. Breakovers (convexities) and transitions (concavities) are places of concern due to the tension differences in the snowpack. So be weary of any blind rollovers.
Exposure: Think of it this way: What will happen if this slides? A long, open run out is a different situation than a terminal cliff or a deep gully that would funnel a slide.
|Last week’s backcountry tip: Pack it up, Pack it in →|