You won’t be spending all of your time at camp, which means you’ll need warm winter clothing – in a sensible layering system – to keep you warm while out hiking, snowshoeing, backcountry skiing, or whatever other activities you intend to take part in. That begins with a set of good baselayers, which sit next to the skin and keep you warm and dry by wicking away moisture. Next, you’ll want a good insulating later – such as a down jacket – to provide warmth, and a shell layer (both jacket and pants) to repel the elements. When each of these items is used together, they provide a good level of protection from the cold, making it much easier to be outside for extended periods of time.
PS: Don’t forget warm socks, gloves, and a hat too!