Easter is real late for the ski industry this coming 2011, April 24, so ski areas like Vail are in a pickle. My guess is that April 17 is not etched in stone by any means. Last time it was late like this or real early, they would say something like the 10th, then add a week. It has been several years since they pulled that trick, and now with work visas being what they are, i think those days are done.
So if anyone has an insider's edge here (Vail,) please post it up cause I habitually end my year here.