The litter composed of leaves, twigs, dead logs, etc., that covers the ground in a forest. The quality and moisture content of duff is important in considerations of forest fire hazards, especially in the early spring before vegetation has started growing. A name given, early in 1935, to the region in the south-central U.S. afflicted by drought and duststorms at that time. It included parts of Colorado, Kansas, Oklahoma, Texas and New Mexico. A small, vigorous, short-duration whirlwind, made visible by dust or other debris carried aloft, ranging up to 100 feet in diameter, average height 600 feet.
Winds are clockwise or counterclockwise.