Cumulonimbus flammagenitus

Cumulonimbus Flammagenitus
The evolution of a Pyrocumulonimbus cloud, caused by backburning, forming over the Blue Mountains and viewed from Hazelbrook, New South Wales.
GenusCumulonimbus
Speciesnone
Altitude500-16,000 m m
(2,000-52,000 ft ft)
AppearanceFast-growing storm cloud that usually has dark ash rising rapidly.
PrecipitationRain, hail or occasional acid rain.
For decades, the plume in this "Hiroshima strike" photo was misidentified as the mushroom cloud (itself a type of cumulonimbus flammagenitus) from the atomic bomb blast on 6 August 1945.[1][2] However, due to its much greater height, the cloud was identified in March 2016 as the cumulonimbus flammagenitus cloud produced above the city[2] by the subsequent firestorm, which reached its peak intensity some three hours after the explosion.[3]
Picture of a cumulonimbus flammagenitus cloud, taken from a commercial airliner cruising at about 10 km altitude.[4]
A satellite image of the formation of a cumulonimbus flammagenitus over Argentina in 2018.

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, nuclear explosion, or volcanic eruption,[5] and may sometimes even extinguish the fire that formed it.[6] 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."[7]

Analogous to the meteorological distinction between cumulus and cumulonimbus, the CbFg 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),[8] hail, lightning, extreme low-level winds, and in some cases even tornadoes.[9] The combined effects of these phenomena can cause greatly increased fire-spread and cause direct dangers on the ground in addition to 'normal' fires.[9][10]

The CbFg was first recorded in relation to fire following the discovery in 1998[8] that extreme manifestations of this pyroconvection caused direct injection of large abundances of smoke from a firestorm into the lower stratosphere.[11][12][13][14][15] 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.[9][16]

In 2002, various sensing instruments detected 17 distinct CbFg in North America alone.[17]

On August 8, 2019, an aircraft was flown through a pyrocumulonimbus cloud near Spokane, Washington, to better study and understand the composition of the smoke particles as well as get a better look at what causes these clouds to form, plus see what kinds of effects it has on the environment and air quality. It was one of the most detailed flights through CbFg to date.[18]


In 2021 alone, an estimated 83 cumulonimbus flammagenitus had formed. [19]

  1. ^ "A Photo-Essay on the Bombing of Hiroshima and Nagasaki". University of Illinois at Urbana-Champaign. Archived from the original on 20 December 2016. Retrieved December 4, 2016.
  2. ^ a b Broad, William J. (May 23, 2016). "The Hiroshima Mushroom Cloud That Wasn't". The New York Times. Archived from the original on December 8, 2016. Retrieved December 4, 2016.
  3. ^ Toon, O. B.; Turco, R. P.; Robock, A.; Bardeen, C.; Oman, L.; Stenchikov, G. L. (2007). "Atmospheric Effects and Societal Consequences of Regional Scale Nuclear Conflicts and Acts of Individual Nuclear Terrorism" (PDF). Atmospheric Chemistry and Physics. 7 (8): 1973–2002. Bibcode:2007ACP.....7.1973T. doi:10.5194/acp-7-1973-2007. ISSN 1680-7316. Archived (PDF) from the original on 28 September 2011. Retrieved 4 December 2016.
  4. ^ Fromm, Michael; Alfred, Jerome; Hoppel, Karl; et al. (May 1, 2000). "Observations of boreal forest fire smoke in the stratosphere by POAM III, SAGE II, and lidar in 1998". Geophysical Research Letters. 27 (9): 1407–1410. Bibcode:2000GeoRL..27.1407F. doi:10.1029/1999GL011200. S2CID 131699797. Archived from the original on January 6, 2009. Retrieved August 29, 2013.
  5. ^ WMO. "Explanatory remarks and special clouds". International Cloud Atlas. Archived from the original on 2019-12-11. Retrieved 2020-01-01.
  6. ^ Csifo, Noemi. "Fire Cloud Cumulus Cumulonimbus Weather". Sciences 360. R R Donelley. Archived from the original on 22 October 2013. Retrieved 22 October 2013.
  7. ^ "AMS Glossary". American Meteorological Society. Archived from the original on 20 December 2019. Retrieved 1 January 2020.
  8. ^ a b Fromm, Michael; Lindsey, Daniel T.; Servranckx, René; Yue, Glenn; Trickl, Thomas; Sica, Robert; Doucet, Paul; Godin-Beekmann, Sophie (2010). "The untold story of pyrocumulonimbus, 2010". Bulletin of the American Meteorological Society. 91 (9): 1193–1210. Bibcode:2010BAMS...91.1193F. doi:10.1175/2010BAMS3004.1.
  9. ^ a b c Fromm, M.; Tupper, A.; Rosenfeld, D.; Servranckx, R.; McRae, R. (2006). "Violent pyro-convective storm devastates Australia's capital and pollutes the stratosphere". Geophysical Research Letters. 33 (5): L05815. Bibcode:2006GeoRL..33.5815F. doi:10.1029/2005GL025161. S2CID 128709657.
  10. ^ Cite error: The named reference :3 was invoked but never defined (see the help page).
  11. ^ Fire-Breathing Storm Systems. NASA
  12. ^ Fromm, Michael; Alfred, Jerome; Hoppel, Karl; et al. (May 1, 2000). "Observations of boreal forest fire smoke in the stratosphere by POAM III, SAGE II, and lidar in 1998". Geophysical Research Letters. 27 (9): 1407–1410. Bibcode:2000GeoRL..27.1407F. doi:10.1029/1999GL011200. S2CID 131699797. Archived from the original on January 6, 2009. Retrieved August 29, 2013.
  13. ^ Fromm, M.; Stocks, B.; Servranckx, R.; et al. (2006). "Smoke in the Stratosphere: What Wildfires have Taught Us About Nuclear Winter". Eos, Transactions, American Geophysical Union. 87 (52 Fall Meet. Suppl): Abstract U14A–04. Bibcode:2006AGUFM.U14A..04F. Archived from the original on October 6, 2014.{{cite journal}}: CS1 maint: unfit URL (link)
  14. ^ Fromm, M.; Servranckx, R. (2003). "Transport of forest fire smoke above the tropopause by supercell convection". Geophysical Research Letters. 30 (10): 1542. Bibcode:2003GeoRL..30.1542F. doi:10.1029/2002GL016820. S2CID 55107591.
  15. ^ Jost, Hans-Jürg; Drdla, Katja; Stohl, Andreas; et al. (June 2, 2004). "In-situ observations of mid-latitude forest fire plumes deep in the stratosphere". Geophysical Research Letters. 31 (11): L11101. Bibcode:2004GeoRL..3111101J. doi:10.1029/2003GL019253. hdl:11858/00-001M-0000-002A-D630-D. CiteID L11101.
  16. ^ Fromm, M.; Stocks, B.; Servranckx, R.; et al. (2006). "Smoke in the Stratosphere: What Wildfires have Taught Us About Nuclear Winter". Eos, Transactions, American Geophysical Union. 87 (52 Fall Meet. Suppl): Abstract U14A–04. Bibcode:2006AGUFM.U14A..04F. Archived from the original on October 6, 2014.{{cite journal}}: CS1 maint: unfit URL (link)
  17. ^ Fire-Breathing Storm Systems. NASA
  18. ^ "Flying through a Fire Cloud". 9 August 2019. Archived from the original on 8 June 2020. Retrieved 20 July 2020.
  19. ^ "Archived copy". Twitter. Archived from the original on 2021-10-05. Retrieved 2021-10-05.{{cite web}}: CS1 maint: archived copy as title (link)