I drive my M3 year round here and the only time I had an issue was on old snow tires - I got stuck on the incline of my driveway which was solid ice.
In general, if you don't push your snows in the dry, or when it heats up, then they should last two solid winters (rears).
The only time you will have issues with snow tires is in deep snow or ice on steep hills. Even then, you will be surprised by the ability of the car to climb, but it won't be a great experience ; ) Most of the time, the various municipalities stay ahead of it, but we have had multiple blizzards the past two years. Actually, the last two winters have been the worst in probably 10+ years.
Good luck - let me know if you have more questions!