Literally means fire cloud. These clouds are produced when a smoke column created by a wildland fire caps out (has an ice cap) creating in all intents and purposes a cumulonimbus cloud. These clouds have been known to produce lightning, hail, light precipitation and on occasions have been known to put out the fire.
Hey take a look at that pyrocumulus that is forming over the wildland fire.
by Alistair MacIlherron September 21, 2009