There are so many things about Hirscher's technique that makes him great, hard to explain in one article. I'll produce and expalin the differences in a number of articles coming up here on my Blog.
First, he skis exactly like PMTS Direct Parallel is described in my "Essentials of Skiing" book and DVDs.
He is also the most "athletically" gifted of all technical skiers in the history of skiing. The combination of perfect technique and great athletic gifts has never happened before, not at this level, we are watching a phenom.
In World Cup skiing, and in any high level skiing, or even when learning skiing, you can't just hold a position, you have to be moving parts of the boody as the turn develops. This is critical in this analysis because the natural forces want to rotate your body out of balance. The skiers job is to not let this happen.
Here you see Hirscher moving the inside half into a stronger relationship to his skis as the arc develops. his inside hand keeps pace with his downward movement on the slope and his arcing skis. Since the inside hand is connected to his arm, shoulder and torso, (the inside half) this always leads where his ski tips are headed. This is a counter acting movement and it strengthens the skeletal alignment as forces build; therefore Hirscher can hold more forces than other skiers. (comparisons to others coming in next article)
The second most obvious part of Hirscher's skiing that most of the other skiers have not come close to acheiving is the way he moves, holds and tips his inside ski and moves his inside ski boot. His inside foot is always closer to the outside boot and knee than any other skier. He holds his inside ski boot back under his hips and pulls his inside ski back while tipping it to a higher angle than all the other skiers, on a consistent basis. This gives him better balance and it allows the outside ski to run a closer line to the gates and higher angles to the snow surface. He then shifts his weight or balance to the inside ski. To exit or release the outside ski he retracts the long leg, never pushing or stepping off or away from the outside ski or off the outside ski. Acheiving this action isn't easy and it's not natural. He has to get extreme flex or bend with the inside leg. This inside foot relationship adds to his perfect skeletal alignment in the crucial part of the arc.
This is just the beginning of my descrpitions of Marcel Hirscher, he makes so many highly technical movements and executes them so well, he makes skiing, at this most extreme level, look easy.