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Josh Hirshberg
Terrain choice is the answer to uncertainty and unstable snow
Terrain choice is the answer to uncertainty and unstable snow
The adage “If the snowpack is the question (or problem), then terrain is the answer" was developed by longtime Utah Avalanche Center forecaster Drew Hardesty. It rings true and applies whether you are going into the backcountry for the first time, or are a seasoned professional. As a backcountry traveler, you obviously can’t control the snow, but you can control where you go, thus controlling what type of avalanche terrain, (if any) that you choose to travel in.
Tool for ruling out terrain: wide paint roller or narrow trim brush?
Tool for ruling out terrain: wide paint roller or narrow trim brush?
The day’s hazard and uncertainty stemming from the conditions and the group will give you an idea of precision with which you will need to choose terrain. Think of it as using different sized paint brushes that you use to paint out (rule out) terrain to determine the type of terrain you are going to limit yourself to for the day.
Using the paintbrush analogy, some specific examples might look like the following:
The 12” paint roller (broad brush): Some days you can’t be in avalanche terrain anywhere so you avoid all avalanche terrain, especially being mindful of avalanche paths and avoiding where avalanches start, run, and stop.
The 4” paint brush (middle brush): You choose to avoid specific aspects and elevations to avoid certain avalanche problems or specify parts of the path to avoid such as generally avoiding start zones and some paths and runouts.
The 1” trim brush (fine brush): You may choose to be on the same slope as the avalanche problem, but you avoid the problem through timing or slope-scale terrain choices such as entering mid-track to avoid a wind slab or avoiding convexities for storm slab problems, or avoiding slopes greater than a specific steepness above terrain traps for loose dry problems.
As the hazard increases, the coarseness of the paintbrush you use to rule out terrain increases. Similarly, as your uncertainty increases, either through lack of familiarity with the conditions, high uncertainty due to the conditions, or dynamics in the group that in some way increase group uncertainty, the size of the brush you use to rule out terrain increases.
Terrain familiarity also drives terrain choices
Terrain familiarity also drives terrain choices
While the hazard for the day, your familiarity with the conditions, and the group may largely drive your terrain use mindset and the precision with which you rule it out, your familiarity with the terrain will also dictate the size of the brush you can employ when choosing terrain. Terrain you are more familiar with, both in physical makeup and the nuances of how it influences conditions throughout the season, allows you to make more detailed terrain choices specifically in response to conditions. Less familiarity with the terrain will mean you need to use broader brush strokes to more conservatively and broadly rule out terrain.
Terrain is both the tool you use and a source of uncertainty in and of itself. The tools and skills you develop are the same both to reduce uncertainty and more effectively use terrain as a tool in response to increasing hazard or uncertainty. Broadly speaking, terrain uncertainty is all about familiarity with the terrain and how conditions play out specifically in the terrain. Making observations about terrain throughout the year, even when there is snow on the ground, and keeping details about a lot of trip options are the way to address familiarity.
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