Part of the difference is labor laws. There are people driving 30km to commute to work with no public transit alternative. Even if it's unsafe to drive, they will make an attempt because they are required to be at work, and they can't wait for the snow plows to come through.

One time I commuted into work when there was 30cm snow, and we got another 30cm during my shift. Most of the employees weren't able to get home, so we slept that night in the store.