Can you use like a heat gun on them to get them thawed enough to start running a trickle of water through them? I don't know, I've never had to deal with frozen pipes. Never had to deal with -21 either.
Seriously, good luck.
And call your insurance agent now if you don't already have flood insurance.
M80v2 | VP150v2 | QS8v2 SVS Pci+ 20-39 Emotiva UMC-1 & LPA-1 M22ti + T-Amp, in the Office