To me the 'boonies' in Canada is west of Timmins, East of Wawa and North of Desbarats in Ontario, and anything North of Kamloops in BC. The roads in BC are very critical infrastructure, there aren't that many of them to begin with and there are a lot of choke points on the downslopes of mountain ranges where you have to pass through, unfortunately it looks as though that's where the road outages are.

Canada is an amazing country scenery wise, but it is also a very thin veneer of civilization on top of a very rugged countryside and it doesn't take much to turn it from workable into unconnected islands overnight. Let's hope that they manage to keep the power running and some way to keep those communities supplied because with winter on the way that can get ugly really quickly.

Canadians are usually pretty self sufficient but without roads I'm not sure how that would work.