Prudent boaters take precautions against ice at the dock as well.
It’s counterintuitive, but in freezing weather, it’s warmer below the water’s surface. So keep your outboard trimmed down in the water to minimize freezing the gear case.
Snow doesn’t drain like water. And even if it melts during the day, chances are good the runoff will freeze in your scuppers by night. Keep a shovel (plastic, to avoid gouging fiberglass) aboard and use it.
Make sure your batteries are up to snuff, and consider wiring in one or two more. Winter storms knock marina power out as readily as household power — and with it, your battery charging capabilities.