Not much help but.....
.... I had a similar dilema when travelling in early May this year. Didn't find any decent sites for the info really (the ski ones just referred to slopes). I'd heard stories of riders going at that time & being snowed in. My trip, however, was great - 1 blocked road that only went to a lake anyway. Saw plenty of snow though.
What time of year are you going?
You'll usually find someone who's just come back, or been at the time your thinking of going.