The term STORM SOUND can be broken down into four crossword solutions: CLAP (4 letters), THUNDERCLAP (11 letters), PEAL (4 letters) and ROAR (4 letters). A CLAP is a sharp sound made by striking two surfaces together, such as hands. A THUNDERCLAP is a loud, sudden CLAP of thunder that is usually accompanied by lightning. A PEAL is a series of loud ringing sounds, such as bells. Finally, a ROAR is a deep, prolonged sound made by an animal or a large crowd. All of these sounds are associated with storms, which often include thunder, lightning and strong winds.