Snow and boats
Canadian Yachting
The boat winterizing process includes: Preparing the boat's systems for long-term storage and Removing water from any/all systems to prevent any freezing damage. Once temperatures drop below freezing (even for one day or night), damage may occur. When water freezes it expands and can easily burst water tanks, water lines, faucets, toilets, waste tanks, engine blocks, exhaust manifolds and mufflers. However, damage can’t be fully known until the engine is run, or water system is pressurized.
Avoid complete panic and read the steps on what you can do - Canadian Yachting covers the steps in the original article here.