I recently purchased a backpack for the upcoming season (just as a small resort one, no sidecountry or backcountry) to keep some water and whatnot in, as I tend to get thirsty throughout the day (and to carry lunch, extra lens, etc...). I saw that the backpack is compatible with water resevoirs, so I was wondering if I needed an insulated water resevoir and tube for the hill, or just the tube? My initial impression is that a resevoir would not get cold enough to freeze (being in my backpack), but I am not too sure. If I go this route I will definitely get an insulated tube, but was wondering if an insulated resevoir is necessary (or recommended) as well? How likely is it to freeze? Thanks for any help!
EDIT: And if anyone knows of any stores in Canada (specifically Calgary) that sell these please list them!