Cumulonimbus flammagenitus (cloud) on the fujita scale, the first confirmed violent fire tornado. The tornado and associated fire killed 4 people and injured 492. Cumulonimbus flammagenitus (cloud) The cumulonimbus flammagenitus cloud (CbFg) 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."
Asperitas (cloud) Asperitas (cloud) Asperitas (formerly known as Undulatus asperatus) is a cloud formation first popularized and proposed as a type of cloud in 2009 by Gavin Pretor-Pinney of the Cloud Appreciation Society. Added to the International Cloud Atlas as a supplementary feature in March 2017, it is the first cloud formation added since cirrus intortus in 1951. The name translates approximately as "roughness". The clouds are closely related to undulatus clouds. Although they appear dark and storm-like, they almost always dissipate without a storm forming. The ominous-looking clouds have been particularly common in the Plains states of the United States, often