Low Thunder Rumble

The downpour of raindrops is steady and rhythmic. It can be heard following the contours of building and gathering in puddles on the ground. In the distance the sound of thunder vibrates in a low rumble. A wet and clean smell permeates everything through the open window. The thunder is preceded by flashes of lightening dividing up the sky. Thunder is the sound caused by lightning. Depending on the distance and nature of the lightning, thunder can range from a sharp, loud crack to a long, low rumble (brontide). The sudden increase in pressureand temperature from lightning produces rapid expansion of the air surrounding and within a bolt of lightning. In turn, this expansion of air creates a sonic shock wave, similar to a sonic boom, which produces the sound of thunder, often referred to as a clap, crack, or peal of thunder. The distance of the lightning can be calculated by the listener based on the time interval from when the lightning is seen to when the sound is heard.