[Motor31]

The first thing I'd try is a 60 to 100 watt trouble light on a cord inside the basement area. Put it in the water control compartment (where the handles are) first to make sure it isn't the handles that are frozen since they really are between the basement and outside. There is an electrical outlet in the basement area so you don't have to worry about threading a cord through the outside basement doors. Kick the furnace up a bit too to get more air circulating. If you have been relying on space heaters that leaves the basement exposed to cold. You might also want to open the cabinet and pantry doors in the kitchen to let more air get in there too.

If you do use a 100 watt light be sure it doesn't sit directly on a tank and melt the tank surface. The black tank valve should be right behind the water heater. I'm not sure where the grey tank valve is.