Subject: Whistler
I don't know if this is 100%... I'm not a skiier, so I assume it depends on the weather.

But ideally, yes, the slopes are open in May. I heard something about a snowboard event being held there in mid-May. I wouldn't normally know this stuff, but I am going on a vacation next month myself and our original destination was BC.

I think their site is or I'm sorry I don't have web access right now to check for sure, but I do know they have a good site, so if these don't work, do a search and it'll come up.

Good luck!