http://www.rotorooter.com/plumbing-basics/seasonal-tips/winter/

Frozen pipe advice from the Roto-Rooter website:

If water freezes in a pipe, the website says, it will expand and crack it. Pipes in attics, garages, crawl spaces or outside walls are the most vulnerable.

To prevent a pipe from freezing:

-Fit pipes with insulation sleeves or wrapping

-Let your faucet drip during extreme cold to prevent bursting

If your pipes are already frozen:

-Turn off your water main to prevent flooding

-Research the piping layout structure in your home

-Identify the cracked pipe and replace the broken sections with insulation

-Call a plumber immediately