When a drain freezes and it causes a clog, it is rather annoying to take a shower and realize that you are standing in, well, standing water. However with a few simple steps, you can clear the clog and unfreeze the drain without a big hassle. You don't even need to remove any pipes or drain covers.
Boil 2 to 3 gallons of water with 1 cup of salt. Salt is very good for melting ice.
Dump 1/2 cup of baking soda down the drain.
Pour 1 cup of vinegar down the drain, this will cause a chemical reaction with the baking soda which will fizz and bubble. This process cleans the pipe and drain to allow everything to be flushed through the pipe when you clear the frozen clog.
Slowly pour the boiling salt water into the drain. This will melt the frozen clog and allow the baking soda and vinegar mixture to penetrate any buildup on the walls of the pipes.
Follow by running hot water into the drain for about 5 minutes to make sure that it is unfrozen and draining well.