STORM There are countless versions of this activity. The basic principle involved is using body percussion to create rain and storm effects. The version in Music Room comes from various music-teaching workshops in Melbourne held in the 1970s. Another version can be found on pp 35-35 of the on-line STOMP study guide.
This version is called A Stormy Beginning and is, in turn, adapted from A Stormy Ending, a Rainforest Curriculum Activity copyright 1991 by Alexander Goldowsky, Education Department, New England Aquarium, Boston, MA.
A performance of Rain, another version of the idea, can be seen on this YouTube clip from Perpetuum Jazzile. Lookout for the Beat Boxing after the rain!