Tahoe skiing

I am visiting a friend who just moved to SF and we plan on going skiing in
Tahoe.  I have a few questions; bear in mind that I have never skied
outside
of NY before, and I am a competent but not daring skier.

1) What is the best time to go?
2) What resorts are best, and why?
3) Are the skis I use here for skiing on ice suitable, or should I rent
skis?
4) What the heck happened here?!  I was last here a year ago and it was
pretty busy.