Races may be won on the climbs, but tours can be ruined on the downhills.
A lot of beginning cross-country skiers dislike the climbs, but fear the downhills. Gravity will not be denied. The steeper the hill, the stronger its power.
Beginner lessons teach the wedge or snowplow for skiers to control speed going down. Place the ski tips together and push the tails apart with your heels. Drop your knees inward to set the inner edges. What could be simpler?
On any skis, downhill or cross-country, the wedge only goes so far. Typically, a beginner who tries to negotiate a whole hill in the wedge will feel the tips spread irresistibly apart, until the hapless skier is hurtling straight down, out of control, with the skis about three feet apart and no hope of getting them back together. Most of us have been there, especially if you took up skiing as an adult. Even if the skier started as a child, some of them never outgrew that straddled stance.
By weighting one ski at a time in the wedge, you can turn back and forth. You don’t really carve a turn. You just go in the direction the ski is already pointed. You can use this effect to help you, not to go around corners, though it works for that, but to control speed more effectively than a simple wedge.
The danger of the wedge is that you get caught with your weight between the skis. You can’t unweight what you never fully weighted. If one or both skis try to wander off and get into trouble, you end up going along for the ride.
By weighting one ski at a time, back and forth, constantly shifting, you improve your chances of staying in control. If the ski you’re on takes a quick swerve, you can shift fully to the other ski. If the other ski gets sidetracked by a rut or a bump, you don’t have weight committed to it, so you can snap it back into line.
As you gain proficiency and confidence you can start narrowing the wedge to make it into a parallel turn. But there will be times when the alternately-weighted wedge will still be the expert’s choice. If the snow is fast, verging on icy, and the trail is rutted up from previous traffic, the wedge provides the most stability. Just don’t get lazy and stop shifting your weight.