I think Nolo's sugestion has great potential to be explored, both with the body and within the mind.
I know my in-line skating up/down hills doing ski turns in the summer has helped my snow skiing.
I also know thinking about transferring the things I've learned thru snow skiing (biomechanics, etc) into my summer waterskiing has helped me get up to speed quicker when I hit the water in the spring.
I reviewed one particular video of very technically accuracte pro slalom waterskiing several times a week all winter while imagining my skiing the same way and felt it contributed to the best off-the-dock and into a slalom course skiing I ever could have wished for on day-1 this spring.
Note, I did not watch a waterski Pro running 41'-off using balistic mega-power movements I will never aspire to, but a Pro with really accurate movements I can relate to smoothly demo'ng 32'-off, which is the stepping stone I am at and aspire to become more consistant at this summer.
The use of imagery in the off season is a powerful tool, if you are watching technically correct movements. If you can relate to those movements, and imagine yourself making them as you watch, you can actually create more consistantly accurate neuro-muscular pathways than what you might normally ski with. If you can imagine the movements, then your body has the capability of making them.
So for snow skiing find video of really clean, consistant skiers showing where you aspire to progress to this next season and let yourself "feel" the movements as you watch them and you can build "cues" to think about to help trigger those movements when you hit the snow.