Plumbers use commercial steam jetters that direct 240°F steam into the pipe. This is the fastest, safest method for deep or buried frozen drains.
If you currently have a frozen pipe, here is a review of the common methods to fix it: frozen drain pipe outside
Gurgling, banging, or clanking sounds when water is running often indicate that water is struggling to move past an ice blockage. Plumbers use commercial steam jetters that direct 240°F