Un[best] Freeze Shower Drain [BEST]

If the frozen section is accessible (like in a crawl space or basement), you can warm the pipe itself.

If the above methods don't work, you can try using a chemical drain cleaner to melt the ice: unfreeze shower drain

Rock salt lowers the freezing point of water. Mix ½ cup salt with 2 cups warm water and pour slowly. Wait 5 minutes, then follow with more warm water. If the frozen section is accessible (like in