We keep all trucks in a heated station so they dont freeze. And as for once at the fire, the trucks can go to a dry hydrant and draft from the water. Because the hydrants are close to the bottom where the water isnt going to freeze
Ice...We use a dump truck with a coal chute:) Just kidding. In Maine we see freezing weather fairly frequently. We drain and antifreeze our pumps w/ methanol from Oct-April, we have both pressurized hydrants which are pumped and checked by the water districts and we have dry hydrants in our rural areas. If necessary we have been know to cut holes through the ice w/ chainsaws to get at the water (wearing PFDs when on ice). We always order heavy planning on having a truck or two freeze up during the operation...tactical reserve and all. We also try to have available some portable propane heaters to apply to the frozen pumps. H2O supply in Nov-April around here is usually a head scratcher no matter what. If we didn't have the winters we would enjoy our other seasons...black fly and mud!
I had a fire at -13, we had 6 of 8 of the responding trucks freeze including both of ours. They were not ordered with pump heaters,(i was not involved in the ordering). That amazes me being here in cold country. I had heaters and under the pump panels installed within weeks of this incident. Our pump heaters are left in the on position in winter and drivers are intructed to begin circulating water as soon as they arrive if not pumping. We do not drain the pumps but do make dure the discharges are drained. we also carry chain saws and an ice auger to access lakes. My advice is to call ots of tankers so you dont have to go to the water right away.