The Sierra has had more snow in the past 2 weeks than any October since at least 1945. These storms have also dumped substantial snow in Utah.
California: Both storms have centered on Mammoth, which has had 82 inches of snow and now has a 4-6 foot base with excellent conditions. Kirkwood has received 71 inches and Squaw 51 at 8,200 ft. and 25 at 6,200 ft. Alpine Meadows, Boreal, Sugar Bowl and Sierra-at-Tahoe also opened for Halloween weekend. See Current California Ski Conditions for more details on Southern California and Mammoth.
Pacific Northwest: No one is open now except Timberline's year-round Palmer lift. Substantial accumulation is reported in the Whistler alpine, but no indication that its scheduled opening of Nov. 20 will be advanced.
Canadian Rockies and Interior B.C.: Lake Louise is making snow for its early World Cup race.
U. S. Northern Rockies: No info yet.
Utah: 4-8 feet of snow have fallen in the past 2 weeks. Brighton is 50% open with 4 lifts and 99 inches of October snowfall, and Snowbird will advance its opening to first weekend of November.
Northern and Central Colorado: Loveland and A-Basin have a couple of runs open on mostly snowmaking. There has been natural snow, but not enough for a skiable base.
Southern and Western Colorado: Wolf Creek is open on 31 inches of recent snowfall. This is likely a thin base with Colorado's drier snow.
Northeast: No reported openings yet. I strongly recommend checking First Tracks Online Ski Magazine No-Bull Ski Reports for up to date information in this region, where both weather and surface conditions can change so rapidly.