@article {bnh-1882,
	title = {Pyrocumulonimbus: A Literature Review},
	year = {2015},
	month = {06/2015},
	abstract = {<p>A pyrocumulus cloud is a dense cumuliform cloud associated with fire or volcanic activity (although here we report only on fire pyrocumulus).\&nbsp; It is produced by intense heating of air, which leads to deep ascent and subsequent condensation when the rising air becomes saturated due to cooling from adiabatic expansion.\&nbsp; The condensation is evident in cloud formation.\&nbsp; The process is similar to conventional convective cloud formation, when a lifting mechanism (e.g., orographic lifting, intersection of two air masses) raises air beyond where the cloud forms (the lifting condensation level) to where the additional condensational heating makes the air positively buoyant (the level of free convection).\&nbsp; Turbulent entrainment of cooler and drier air from outside the rising airmass dilutes the cloud buoyancy, which can limit the size and growth of the cloud (e.g., fair weather cumulus).\&nbsp; At the opposite extreme, larger and more intense lifted regions can accelerate to the tropopause. As they cross the tropopause into the much more stable air in the stratosphere, they become cooler than the ambient air, and hence negatively buoyant. However, they may possess enough momentum that they overshoot the level of neutral buoyancy\&nbsp; Outflowing air at the tropopause gives these cumulonimbus clouds their classic anvil shape (a nimbus cloud is a cloud that produces precipitation).\&nbsp; Evaporation of moisture by entrained dry air in these clouds leads to cooling and descent and the release of previously suspended precipitation, which can result in heavy downpours and intense downburst winds.</p>},
	author = {KJ Tory and W. Thurston}
}
