Pyrocumulonimbus cloud

The cumulonimbus flammagenitus cloud (CbFg), also known as the pyrocumulonimbus cloud, is a type of cumulonimbus cloud that forms above a source of heat, such as a wildfire, and may sometimes even extinguish the fire that formed it. It is the most extreme manifestation of a flammagenitus cloud. According to the American Meteorological Society’s Glossary of Meteorology, a flammagenitus is 'a cumulus cloud formed by a rising thermal from a fire, or enhanced by buoyant plume emissions from an industrial combustion process.' Analogous to the meteorological distinction between cumulus and cumulonimbus, the cumulonimbus flammagenitus is a fire-aided or –caused convective cloud, like a flammagenitus, but with considerable vertical development. The CbFg reaches the upper troposphere or even lower stratosphere and may involve precipitation (although usually light), hail, lightning, extreme low-level winds, and in some cases even tornadoes. The cumulonimbus flammagenitus cloud (CbFg), also known as the pyrocumulonimbus cloud, is a type of cumulonimbus cloud that forms above a source of heat, such as a wildfire, and may sometimes even extinguish the fire that formed it. It is the most extreme manifestation of a flammagenitus cloud. According to the American Meteorological Society’s Glossary of Meteorology, a flammagenitus is 'a cumulus cloud formed by a rising thermal from a fire, or enhanced by buoyant plume emissions from an industrial combustion process.' Analogous to the meteorological distinction between cumulus and cumulonimbus, the cumulonimbus flammagenitus is a fire-aided or –caused convective cloud, like a flammagenitus, but with considerable vertical development. The CbFg reaches the upper troposphere or even lower stratosphere and may involve precipitation (although usually light), hail, lightning, extreme low-level winds, and in some cases even tornadoes. The CbFg was named following the discovery in 1998, that extreme manifestations of this pyroconvection caused direct injection of large abundances of smoke from a firestorm into the lower stratosphere. The aerosol of smoke comprising CbFg clouds can persist for weeks, and with that, reduce ground level sunlight in the same manner as the “nuclear winter' effect. A cumulonimbus flammagenitus may often form from the eruption column of a volcano. In 2002, various sensing instruments detected 17 distinct cumulonimbus flammageniti in North America alone. Alternate spellings and abbreviations for cumulonimbus flammagenitus that may be found in the literature include Cb-Fg, pyrocumulonimbus, pyro-cumulonimbus, pyroCb, pyro-Cb, pyrocb, and pyro-cb. The World Meteorological Organization does not recognize the cumulonimbus flammagenitus as a distinct cloud type, but instead classifies it simply as cumulonimbus. On 18 January 2003, a supercell thunderstorm formed from a cumulonimbus flammagenitus cloud associated with a severe wildfire, during the 2003 Canberra bushfires in Canberra, Australia. The supercell resulted in a large fire tornado, rated at EF3 on the fujita scale, the first confirmed violent fire tornado. The tornado and associated fire killed 4 people and injured 492.