Do the best you can to keep the water flowing-
Pull the hosereel out of the van, plug your pole in as soon as you can to get the water flowing.
Dont put the pole up against the building or on the floor for any length of time without water flowing- put it back in the van.
Where you can, leave the van running with the heater on.
These measures are for conditions of 0 degrees or less but for -5 and below forget it......
Marcus...