Crust season is upon us, though the ability to stay on the surface depends greatly on aspect, or degree of exposure to the sun. South facing and flat, open aspects have gotten plenty saturated during the warmth of these past sunny days, so that with the firming chill of overnight lows, these surfaces are plenty supportive. North facing and semi-shaded aspects are less predictable and allow skis to sometimes sink into the crust just enough to lock your ski in place. This infamous “breakable crust” condition is perhaps one of the most challenging condition to master, and possibly one of the more hazardous conditions for the health of a skier’s knee.
Whether in powder, packed trail, corn, groomed corduroy or most other skiing surfaces, we grow accustomed to steering our skis by turning them with just the right amount of pressure and edge angle so that the ski either floats through a turn, carves crisply around in an arc, or skids around into new directions as we manage our speed and direction in gliding down a slope. With the right conditions, this is how we ski with fluidity, efficiency, grace and ease.
Breakable crust changes all that, as once a ski sinks into the surface, turning it through this cold-hardened material is no longer a possibility. Attempting to do so places a great degree of stress on the hinge joint that is not designed in such a way as to resist such twisting forces.
Two strategies that can be effective in approaching these conditions, may help a skier out of a jam. The simplest and perhaps easiest, though less glorious method of surviving breakable crust is the step turn. This turn can be applied when on any surface but it becomes essential when one sinks into the upper surface of consolidated snow. Simply put, this involves lifting the inside ski, pivoting it outward into the new direction of the turn, placing it back down and quickly bringing the other ski alongside it. This is repeated with short, quick movements until one has turned to the desired amount.
Another, less graceful approach to breakable crust is the hop turn. This can only be done with sturdy skis, as it is much more energetic and forceful, and could lead to the demise of a lightweight cross-country ski. It is more useful on the steeper pitches where even step turns cannot manage speed effectively. The hop turn is a variation of the “Christie” or parallel turn that alpine skiers use all day long, though it can be done in the telemark stance just as well. The difference lies in varying the timing and degree of the usual pattern of movements. As the skis do not turn on or in the snow, the only other option is to turn them when they are not trapped in the snow, in other words, in the air.
Facing the torso downhill, with the skis across the hill, the skier coils down, bending the leg joints deeply as one would when preparing for any other hop or jump. The skier then hops up followed by a lifting of both skis out of the snow and a rapid turning of the skis across the fall-line of the slope into the opposite direction, with the torso still facing down the hill and punching the skis firmly into the crust in a blocking type of movement. This can be repeated rhythmically back and forth, without permitting much if any forward glide, creating a zig-zag path down the hill. While this technique requires a certain level of athleticism and energy, and is much less efficient than turns that keep skis in contact with the snow, with practice it can get you down the hill without eating a face-full of crust.
Most skiers that pursue the sports of skiing at resorts where snow is groomed will never have to face this challenge. Off-trail skiers however, face vastly more variable conditions. Hopefully your path choices will steer clear of the need for these techniques, but knowing that they are an option and practicing them in other less stressful situations can prepare you with an approach to handling yourself when faced with challenging snow.