Bib Snow Pants

Bib Snow Pants
What are some good pants for moderate to high activity in heavy snow and freezing cold?

This will be my first winter doing search and rescue in Colorado. I need a pair of excellent outerwear pants or bibs that will keep me warm in very cold temperatures and heavy snow.
I'll be doing a lot of hiking/trudging through snow at a purposeful pace (obviously I'm not just leisurely strolling along when someone's missing) and there's always the potential that we'll need to carry someone out which is extremely strenous.
So ideally the pants will be very warm, waterproof, breathable or vent-able, very tough, allow for adequate range of motion, and be fairly easily taken off if need be. Gaiters would be really helpful too.
I'd like some specific brands and styles, preferably that you've worn before. I know in general what type of pant I need, I need specifics. Thank you in advance for any help

For heavy snow you'd definetely want bibs over pants. Keep the snow out! For bibs I'd recommend snowmobiling bibs over ski or snowboard bibs as they come up higher, more protection for your front and back. Problem is your looking for something that's insulated for cold temperatures and breathable for high activity, not easy! The bibs I'd recommend you look into is the Klim Togwotee Bib. Klim makes apparel for extreme snowmobile riders. They aren't insulated but they do have everything else you listed on what your looking for. For high activity you would be better off getting an uninsulated garment and layering underneath (fleece pants or thermal underwear).

Bib Style Snow Pants