Give me a list of some of the best ski areas spread across the North America. Organize the list by the mountain region they belong to. Give a very short synopsis if desired about why that resort was selected.
Any list of top Ski resorts is one that will be very contested among skiers, but here are a few that stand out:

Pacific Northwest:
Whistler Blackcomb - One of the largest ski resorts in the world, peak to peak gondola, and a vibrant base area village
Mount Baker - Large amount of snow, one of the few remaining locally owned resorts
Crystal Mountain - The largest ski area in Washington state, impressive views of Mt Rainier
Mt Bachelor - Ski lift to the summit and can ski circumnavigate the base of the mountain

Canadian Rockies:
Revelstoke - Highest vertical lift in Canada
Red Mountain - Remote and short lift lines

US Rockies:
Alta - Famous Skiers only mountain with expansive bowls
Park City - Large open terrain with a vibrant village
Crested Butte - Some of the steepest most challenging terrain in the world
Big Sky - Peak gondola to access some of the most challenging terrain in the US
Jackson Hole - Some of the best and most abundant powder and home of famous Corbetts Couloir 

Sierra range:
Tahoe/Palisades: Large resort with expansive views of Lake Tahoe

East Coast:
Stowe Mountain - One of the oldest ski resorts in the US, home of the 10th mountain division
Burke Mountain - Home of the US Ski Race team


In total, there are 826 ski resorts in North America - all are loved for different reasons and have passionate groups of skiers and snowboarders that consider them home, and might argue why their mountain is the best mountain.