During more extreme weather and when the roads are heavily covered with snow or are icy you may want to consider using transit. While the main roads will usually be cleared as soon as snow begins to fall, side streets will often still have significant snow cover hours, or even days after a major snow fall. Off-road paths through city parks are not maintained during winter and will likely be covered with snow and ice you may not be able to use your usual commute route. This is by no means a complete or comprehensive list but should be enough to get you going. Dress warmly, be careful, and most of all have fun cycling this winter.
Many people think that shovelling snow into the road is a good idea.
You see people doing it all the time. They take a shovel-full and throw it out into the road. Maybe they think it will melt faster. Maybe they think that the snowplow will come and take it away. What actually happens is that a few cars roll over it, pack it down and turn it into ice.