Mr Step Turn's description of flying into wind towards rising terrain and subsequent loss of height while turning away from the terrain sounds to me (as a ridge soaring glider pilot) a lot like sink being generated by the air mass flowing down the lee side of the mountain/ridge. And you can lose an awful lot of height turning in sink! Maybe not so much to do with the inertia issue being discussed
However returning to the inertia issue, if you're soaring close to a ridge in gusty conditions, for the sake of your health, you do it a lot faster than when it's calmer!