Pyrocumulonimbus

Pyrocumulonimbus is the most extreme manifestation of a Pyrocumulus cloud. Similarly to the distinction between Cumulus and Cumulonimbus, Pyrocumulonimbus is also caused by fire-assisted convection, like a Pyrocumulus, but with considerable vertical development. A Pyrocumulonimbu strikes the upper part of the troposphere, or even the lower parts of the stratosphere, and can cause precipitation (though generally light), hail, lightning, high winds and, in some cases, even tornadoes.

On January 18, 2003, a supercell was formed from a Pyrocumulonimbus cloud associated with a severe fire in Canberra, Australia. The supercell resulted in a huge fire tornado rated F3 on the Fujita scale, as well as black hail drop.