score:3
Depends a great deal where you're driving. In general, you can get away with normal tires in regular conditions provided the roads have been cleared. So major highways are probably plowed/salted. But there are some roads in that area with special restrictions.
Snow tires or chains are required by law for travel on Hwy #93N / Icefields Parkway and Hwy #93S (Banff-Windermere Highway in Banff National Park and Kootenay National Park) between November 1 and March 31 or any other period during which the highway is covered with snow or ice.
Considering that Highway 93 is both remote and mountainous, it seems like an exception.
Upvote:2
It is not mandatory in Alberta. (I really wonder about that, seriously)
I would never drive up the moutains without winter tires; even on regular roads.
It is not only about snow, ice, it is about temperature, regular tires are not meant for cold temperature and will loose tracktion as it come down below 5c or 6c.
You never know when snow or sleet or freezing rain can start falling and you do not want to be unprepared.
Just get winter tires; and if you are renting a car, ask to have winter tires.