Whistler is fairly low in altitude at the base and too near the coast so you can get warm wet fronts coming in that can melt the snow (water is very good for doing that) or at least soften it.

If you want powder/drier snow, you might want to consider the interior ski resorts (Apex Alpine, Big White & Silver Star - accessible from Kelowna (YLW)) which are higher in altitude, drier and cooler. Night life may be a little bit slow there, though (ain't no San Carlos de Bariloche - more like San Martin de los Andes unless you go to Kelowna).

As for air fare, you can get from MEX-SEA (UA/MX)for $374 exc. tax/fees. About $120-160 for SEA-YVR/YLW on AS.

Click here for B.C. snow reports.