I wouldn't say Montréal is more dangerous, but it is 100% more complicated for drivers. There are so many variables that change suddenly. A road is fully plowed and salted, you turn right and everything turns to shit with tons of snow on the ground. You keep going, suddenly there's ice *underneath* a layer of snow so the car starts skidding, and the plow's going the other way trying not to swallow your car whole.

You're talking about one variable I'm familiar with, but it's one variable. With snow cover in a plain, you just drive much slower and turn on your hazards.

The most complicated scenario, imho, is getting on and off a car ferry. Dark. Wet. Pedestrians. Dogs. No sidewalks. Flashing lights and lots of signs, most of which have nothing to do with car traffic. Lines on the road which you ignore in favor of following hand gestures. Then dramatic up/down ramps followed by parking way too close to other cars. And it is all in a metal box where GPS fails and internal systems are thrown off by ship movements.