Tarp or some other buffer probably isn't a bad idea in case of winter storms, just make sure to not put it tight over the vent, as you still need it good ventilation in winter to allow moist air to escape.
There's various styles of heated waterers. I currently use a nipple waterer with built in heater. Or you can use a heated base as above, or a de-icer, or even an aquarium heater (not really built for it but I used to use one).