Can you rent a propane heater (I think they call them a Salamander) and create an enclosure to put some heat under there to defrost the pipes? Don't know if that's possible especially when it's that cold.
Yes I have one and been on for an hour or two yesterday. I started at the end of the pipe that takes a dive in the ground and been working my way to the end of the pipe. Out of propane will get more today.