Disastrous rhymes with:
ambidextrous, dextrous, estrous, estrus, headmistress, lustrous, mistress, monstrous, actress, ambidextrous, beatrice, buttress, citrus, dextrous, estrous, estrus, fortress, headmistress, idolatrous, kontras, lustrous, mattress, mistress, monstrous, nitrous, peatross, petrus, sentras, waitress, watrous
Disastrous sounds like:
daughter's, daughters, daughters', decoders, degutare's, destroyers, destroys, detectors, dexter's, dextrose, dextrous, dictators, disasters, distress, distresses, distrigas, doctor's, doctors, doctors', dusters