View source for Cumulus cloud

{{short description|Genus of clouds, low-level cloud}}
{{redirect|Cumulus}}
{{Good article}}
{{Infobox cloud type
| name           = Cumulus
| image location = GoldenMedows.jpg
| image name     = Small ''cumulus humilis'' clouds that can have noticeable vertical development and clearly defined edges.
| abbreviation   = Cu
| symbol         = Clouds CL 1.svg
| genus          = Cumulus (heap)
| species        = * [[fractus cloud|Fractus]]
* [[cumulus humilis cloud|Humilis]]
* [[cumulus mediocris cloud|Mediocris]]
* [[cumulus congestus cloud|Congestus]]
| variety        = * Radiatuse
| altitude_m     = 200{{ndash}}2,000
| altitude_ft    = 1,000{{ndash}}6,600
| level          = low
| appearance     = Low-altitude, fluffy heaps of clouds with cotton-like appearance.
| precipitation  = Uncommon [[rain]], [[snow]], or [[graupel|snow pellets]]
| thinkness      = 
| ice content    = 
}}

'''Cumulus clouds''' are [[cloud]]s that have flat [[cloud base|bases]] and are often described as puffy, cotton-like, or fluffy in appearance. Their name derives from the [[Latin]] {{wikt-lang|la|cumulus}}, meaning "heap" or "pile".<ref name="CRH-NOAA" /> Cumulus clouds are low-level clouds, generally less than {{cvt|2000|m|ft}} in [[altitude]] unless they are the more vertical [[cumulus congestus]] form. Cumulus clouds may appear by themselves, in lines, or in clusters.

Cumulus clouds are often precursors of other types of clouds, such as [[cumulonimbus cloud|cumulonimbus]], when influenced by weather factors such as [[atmospheric instability|instability]], [[humidity]], and [[temperature gradient]]. Normally, cumulus clouds produce little or no precipitation, but they can grow into the precipitation-bearing cumulus congestus or cumulonimbus clouds. Cumulus clouds can be formed from [[water vapour]], [[supercooling|supercooled]] water droplets, or [[ice crystals]], depending upon the [[ambient temperature]]. They come in many distinct subforms and generally cool the earth by reflecting the incoming [[solar irradiance|solar radiation]].

Cumulus clouds are part of the larger category of free-convective cumuliform clouds, which include cumulonimbus clouds. The latter genus-type is sometimes categorized separately as [[list of cloud types|cumulonimbiform]] due to its more complex structure that often includes a cirriform or [[anvil]] top.<ref name="LANDSAT identification">{{cite web |last1=Barrett|first1=E. C. |last2=Grant|first2=C. K. |year=1976 |title=The identification of cloud types in LANDSAT MSS images |url=http://www.ntis.gov/search/product.aspx?ABBR=E7610277 |publisher=[[NASA]] |url-status=dead |archive-url=https://web.archive.org/web/20131005000819/http://www.ntis.gov/search/product.aspx?ABBR=E7610277 |archive-date=2013-10-05 |access-date=2012-08-22}}</ref> There are also cumuliform clouds of limited convection that comprise [[stratocumulus]] (low-[[wikt:étage|étage]]), [[altocumulus]] (middle-étage) and [[cirrocumulus]] (high-étage).<ref>{{cite web |url=http://www-das.uwyo.edu/~geerts/cwx/notes/chap08/cumuliform.html |title=Cumuliform Clouds: Some Examples |last=Geerts|first=B. |date=April 2000 |work=Resources in Atmospheric Sciences |publisher=[[University of Wyoming]] College of Atmospheric Sciences |access-date=2013-02-11}}</ref> These last three genus-types are sometimes classified separately as stratocumuliform.<ref name="LANDSAT identification"/>

== Formation ==
[[File:Bubbles in the Sky.ogv|thumb|right|Cumulus clouds forming over the [[Congo River basin]]]]
Cumulus clouds form via [[atmospheric convection]] as air warmed by the surface begins to rise. As the air rises, the temperature drops (following the [[lapse rate]]), causing the [[relative humidity]] (RH) to rise. If convection reaches a certain level the RH reaches one hundred percent, and the "wet-adiabatic" phase begins. At this point a positive feedback ensues: since the RH is above 100%, water vapor condenses, releasing [[latent heat]], warming the air and spurring further convection.

In this phase, water vapor condenses on various nuclei present in the air, forming the cumulus cloud. This creates the characteristic flat-bottomed puffy shape associated with cumulus clouds.<ref name="USA Today">{{cite news|url=http://usatoday30.usatoday.com/weather/wcumulus.htm|work=Weather|title=Cumulus clouds|access-date=16 October 2012|date=16 October 2005|archive-date=28 June 2017|archive-url=https://web.archive.org/web/20170628202558/http://usatoday30.usatoday.com/weather/wcumulus.htm|url-status=dead}}</ref><ref name="Stommel91">{{harvnb|Stommel|1947|p=91}}</ref> The height of the cloud (from its bottom to its top) depends on the temperature profile of the atmosphere and of the presence of any [[Inversion (meteorology)|inversions]].<ref name="Mossop632-634">{{harvnb|Mossop|Hallett|1974|pp=632&ndash;634}}</ref> During the convection, surrounding air is [[Entrainment (meteorology)|entrained]] (mixed) with the [[thermal]] and the total mass of the ascending air increases.<ref name="Langmuir175" />
Rain forms in a cumulus cloud via a [[Cloud physics|process]] involving two non-discrete stages. The first stage occurs after the droplets coalesce onto the various nuclei. Langmuir writes that surface tension in the water droplets provides a slightly higher pressure on the droplet, raising the [[vapor pressure]] by a small amount. The increased pressure results in those droplets evaporating and the resulting water vapor condensing on the larger droplets. Due to the extremely small size of the evaporating water droplets, this process becomes largely meaningless after the larger droplets have grown to around 20&nbsp;to 30&nbsp;[[micrometre]]s, and the second stage takes over.<ref name="Langmuir175">{{harvnb|Langmuir|1948|p=175}}</ref> In the accretion phase, the raindrop begins to fall, and other droplets collide and combine with it to increase the size of the raindrop. Langmuir was able to develop a formula<ref name="formula" group="note">The formula was <math>t={18\eta \over Egwr_0}</math>, with <math>t</math> being the time to infinite radius, <math>\eta</math> being the viscosity of air, <math>E</math> being the fractional percentage of water droplets accreted per unit volume of air that the drop falls through, <math>w</math> being the concentration of water in the cloud in grams per cubic metre, and <math>r_0</math> being the initial radius of the droplet.</ref> which predicted that the droplet radius would grow unboundedly within a discrete time period.<ref name="Langmuir177">{{harvnb|Langmuir|1948|p=177}}</ref>

== Description ==
[[File:Brittany 01.jpg|thumb|Lines of cumulus clouds over [[Brittany]], France]]
The liquid water density within a cumulus cloud has been found to change with height above the cloud base rather than being approximately constant throughout the cloud. In one particular study, the concentration was found to be zero at cloud base. As altitude increased, the concentration rapidly increased to the maximum concentration near the middle of the cloud. The maximum concentration was found to be anything up to 1.25&nbsp;grams of water per kilogram of air. The concentration slowly dropped off as altitude increased to the height of the top of the cloud, where it immediately dropped to zero again.<ref name="Stommel94">{{harvnb|Stommel|1947|p=94}}</ref>

Cumulus clouds can form in lines stretching over {{convert|480|km|mi}} long called cloud streets. These cloud streets cover vast areas and may be broken or continuous. They form when [[wind shear]] causes horizontal circulation in the atmosphere, producing the long, tubular cloud streets.<ref name="Weston433">{{harvnb|Weston|1980|p=433}}</ref> They generally form during [[anticyclone|high-pressure systems]], such as after a cold front.<ref name="Weston437-438">{{harvnb|Weston|1980|pp=437&ndash;438}}</ref>

The height at which the cloud forms depends on the amount of moisture in the thermal that forms the cloud. Humid air will generally result in a lower cloud base. In [[Temperateness|temperate]] areas, the base of the cumulus clouds is usually below {{convert|550|m|ft}} above ground level, but it can range up to {{convert|2400|m|ft}} in altitude. In arid and mountainous areas, the cloud base can be in excess of {{convert|6100|m|ft}}.<ref name="nws-jetstream" />

Cumulus clouds can be composed of [[ice crystal]]s, water droplets, [[supercooled water]] droplets, or a mixture of them.<ref name="CRH-NOAA">{{cite web|title=Cloud Classification and Characteristics|url=http://www.crh.noaa.gov/lmk/?n=cloud_classification|url-status=dead|archive-url=https://web.archive.org/web/20121017002436/http://www.crh.noaa.gov/lmk/?n=Cloud_classification|archive-date=17 October 2012|access-date=18 October 2012|publisher=[[National Oceanic and Atmospheric Administration]]}}</ref>

One study found that in temperate regions, the cloud bases studied ranged from {{convert|500|to|1500|m|ft}} above ground level. These clouds were normally above {{convert|25|C|F}}, and the concentration of droplets ranged from {{convert|23|to|1300|/cm3|/cuin|abbr=off|adj=pre|droplets}}. This data was taken from growing isolated cumulus clouds that were not precipitating.<ref name="Warner1049">{{harvnb|Warner|1969|p=1049}}</ref> The droplets were very small, ranging down to around 5&nbsp;[[micrometre]]s in diameter. Although smaller droplets may have been present, the measurements were not sensitive enough to detect them.<ref name="Warner1051">{{harvnb|Warner|1969|p=1051}}</ref> The smallest droplets were found in the lower portions of the clouds, with the percentage of large droplets (around 20&nbsp;to 30&nbsp;micrometres) rising dramatically in the upper regions of the cloud. The droplet size distribution was slightly [[bimodal]] in nature, with peaks at the small and large droplet sizes and a slight trough in the intermediate size range. The [[skewness|skew]] was roughly neutral.<ref name="Warner1052">{{harvnb|Warner|1969|p=1052}}</ref> Furthermore, large droplet size is roughly inversely proportional to the droplet concentration per unit volume of air.<ref name="Warner1054">{{harvnb|Warner|1969|p=1054}}</ref> 

In places, cumulus clouds can have "holes" where there are no water droplets. These can occur when winds tear the cloud and incorporate the environmental air or when strong downdrafts evaporate the water.<ref name="Warner1056">{{harvnb|Warner|1969|p=1056}}</ref><ref name="Warner1058">{{harvnb|Warner|1969|p=1058}}</ref>

=== Subforms ===
[[File:Cumulusmediocrissweden.jpg|thumb|''Cumulus mediocris'' clouds over [[Sweden]]]]
Cumulus clouds come in four distinct species, ''cumulus humilis'', ''mediocris'', ''congestus'', and ''fractus''. These species may be arranged into the variety, ''cumulus radiatus'', and may be accompanied by up to seven supplementary features, ''cumulus pileus'', ''velum'', ''virga'', ''praecipitatio'', ''arcus'', ''pannus'', and ''tuba''.<ref name="WMO"/><ref name="Pretor-Pinney17">{{harvnb|Pretor-Pinney|2007|p=17}}</ref>

The species ''Cumulus fractus'' is ragged in appearance and can form in clear air as a precursor to cumulus humilis and larger cumulus species-types, or it can form in precipitation as the supplementary feature ''pannus'' (also called [[Scud (cloud)|scud]]) which can also include stratus fractus of bad weather.<ref>{{cite web|title=L7 Clouds: Stratus fractus (StFra) and/or Cumulus fractus (CuFra) bad weather|url=http://www.srh.noaa.gov/jetstream/synoptic/l7.htm|url-status=dead|archive-url=https://web.archive.org/web/20120118151256/http://www.srh.noaa.gov/jetstream/synoptic/l7.htm|archive-date=18 January 2012|access-date=11 February 2013|work=JetStream - Online School for Weather: Cloud Classifications|publisher=National Weather Service}}</ref><ref>{{cite encyclopedia|editor-first=Michael |editor-last=Allaby|encyclopedia=A Dictionary of Ecology|title=Pannus |edition=4th|year=2010 |publisher=Oxford University Press|isbn=978-0-19-956766-9|doi=10.1093/acref/9780199567669.001.0001}}</ref> ''Cumulus humilis'' clouds look like puffy, flattened shapes. ''Cumulus mediocris'' clouds look similar, except that they have some vertical development. ''Cumulus congestus'' clouds have a cauliflower-like structure and tower high into the atmosphere, hence their alternate name "towering cumulus".<ref name="TWC" /> The variety ''Cumulus radiatus'' forms in radial bands called cloud streets and can comprise any of the four species of cumulus.<ref name="Pretor-Pinney20">{{harvnb|Pretor-Pinney|2007|p=20}}</ref>

Cumulus supplementary features are most commonly seen with the species congestus. ''Cumulus virga'' clouds are cumulus clouds producing [[virga]] (precipitation that evaporates while aloft), and ''cumulus praecipitatio'' produce precipitation that reaches the Earth's surface.<ref name="Dunlop77-78">{{harvnb|Dunlop|2003|pp=77&ndash;78}}</ref> ''Cumulus pannus'' comprise shredded clouds that normally appear beneath the parent cumulus cloud during precipitation. ''Cumulus arcus'' clouds have a [[gust front]],<ref name="Ludlum473">{{harvnb|Ludlum|2000|p=473}}</ref> and ''cumulus tuba'' clouds have [[funnel clouds]] or [[tornado]]es.<ref name="Dunlop79">{{harvnb|Dunlop|2003|p=79}}</ref> ''Cumulus pileus'' clouds refer to cumulus clouds that have grown so rapidly as to force the formation of [[Pileus (meteorology)|pileus]] over the top of the cloud.<ref>{{harvnb|Garrett et al.|2006|page=i}}</ref> ''Cumulus velum'' clouds have an ice crystal veil over the growing top of the cloud.<ref name="WMO">{{Cite web|url=http://www.weatheranswer.com/public/Clouds_WMO.pdf |archive-url=https://web.archive.org/web/20050226160200/http://www.weatheranswer.com/public/Clouds_WMO.pdf |archive-date=2005-02-26 |url-status=live|access-date=18 October 2012|title=WMO classification of clouds|publisher=World Meteorological Organization}}</ref>
There are also cumulus cataractagenitus, which are formed by waterfalls.<ref>{{cite web |title=Cataractagenitus |url=https://cloudatlas.wmo.int/en/cataractagenitus.html |publisher=International Cloud Atlas}}</ref>

== Forecast ==
[[Cumulus humilis]] clouds usually indicate fair weather.<ref name="TWC">{{cite web|url=http://www.weather.com/glossary/c.html |title=Weather Glossary |publisher=[[The Weather Channel]] |access-date=18 October 2012 |url-status=dead |archive-url=https://web.archive.org/web/20121017165021/http://www.weather.com/glossary/c.html |archive-date=17 October 2012 }}</ref> Cumulus mediocris clouds are similar, except that they have some vertical development, which implies that they can grow into [[cumulus congestus]] or even [[cumulonimbus cloud]]s, which can produce heavy rain, lightning, severe winds, hail, and even [[tornado]]es.<ref name="USA Today" /><ref name="TWC" /><ref name="WeatherThompson">{{cite book|last=Thompson|first=Philip|author2=Robert O'Brien|title=Weather|url=https://archive.org/details/weather00thom|url-access=registration|publisher=Time Inc.|location=New York|year=1965|pages=[https://archive.org/details/weather00thom/page/86 86–87]}}</ref> [[Cumulus congestus]] clouds, which appear as towers, will often grow into [[cumulonimbus]] storm clouds. They can produce precipitation.<ref name="TWC" /> [[Glider aircraft|Glider]] pilots often pay close attention to cumulus clouds, as they can be indicators of rising air drafts or [[thermal]]s underneath that can suck the plane high into the sky&mdash;a phenomenon known as [[cloud suck]].<ref name="Pagen-105-108">{{harvnb|Pagen|2001|pp=105&ndash;108}}</ref>

== Effects on climate ==
[[File:Anvil of Cumulonimbus and Cu con.JPG|thumb|right|''Cumulus congestus'' clouds compared against a cumulonimbus cloud in the background]]
Due to reflectivity, clouds cool the earth by around {{convert|12|C-change|abbr=on}}, an effect largely caused by stratocumulus clouds. However, at the same time, they heat the earth by around {{convert|7|C-change|abbr=on}} by reflecting emitted radiation, an effect largely caused by [[cirrus cloud]]s. This averages out to a net loss of {{convert|5|C-change|abbr=on}}.<ref name="cloud-heating">{{cite web |url=http://isccp.giss.nasa.gov/role.html|title=Cloud Climatology|work=International Satellite Cloud Climatology Program|publisher=National Aeronautics and Space Administration|access-date=12 July 2011}}</ref> Cumulus clouds, on the other hand, have a variable effect on heating the Earth's surface.<ref>{{cite web|title=Will Clouds Speed or Slow Global Warming?|publisher=National Science Foundation|url=https://www.nsf.gov/news/special_reports/clouds/question.jsp|url-status=dead|archive-url=https://web.archive.org/web/20130129231359/http://www.nsf.gov/news/special_reports/clouds/question.jsp|archive-date=29 January 2013|access-date=23 October 2012}}</ref> The more vertical ''cumulus congestus'' species and cumulonimbus genus of clouds grow high into the atmosphere, carrying moisture with them, which can lead to the formation of cirrus clouds. The researchers speculated that this might even produce a positive feedback, where the increasing upper atmospheric moisture further warms the earth, resulting in an increasing number of ''cumulus congestus'' clouds carrying more moisture into the upper atmosphere.<ref name="Nature384">{{harvnb|Del Genfo|Lacis|Ruedy|1991|p=384}}</ref>

== Relation to other clouds ==
Cumulus clouds are a genus of free-convective low-level cloud along with the related limited-convective cloud stratocumulus. These clouds form from ground level to {{convert|2000|m|ft}} at all latitudes. Stratus clouds are also low-level. In the middle level are the alto- clouds, which consist of the limited-convective stratocumuliform cloud altocumulus and the stratiform cloud altostratus. Mid-level clouds form from {{convert|2000|m|ft}} to {{convert|7000|m|ft}} in polar areas, {{convert|7000|m|ft}} in temperate areas, and {{convert|7600|m|ft}} in tropical areas. The high-level cloud, cirrocumulus, is a stratocumuliform cloud of limited convection. The other clouds in this level are cirrus and cirrostratus. High clouds form {{convert|3000|to|7600|m|ft}} in high latitudes, {{convert|5000|to|12000|m|ft}} in temperate latitudes, and {{convert|6100|to|18000|m|ft}} in low, tropical latitudes.<ref name="nws-jetstream" /> Cumulonimbus clouds, like cumulus congestus, extend vertically rather than remaining confined to one level.<ref name="cumulonimbus-incus">{{cite web|url=http://epod.usra.edu/blog/2009/08/cumulonimbus-incus.html|title=Cumulonimbus Incus|date=5 August 2009|publisher=Universities Space Research Association|access-date=23 October 2012}}</ref>

=== Cirrocumulus clouds ===
[[File:Cirrocumulus in Hong Kong.jpg|thumb|alt=A large field of cirrocumulus clouds in a blue sky, beginning to merge near the upper left.|A large field of cirrocumulus clouds]]
{{main article|Cirrocumulus cloud}}

Cirrocumulus clouds form in patches<ref name="YDN-364">{{harvnb|Miyazaki|Yoshida|Dobashi|Nishita|2001|p=364}}</ref> and cannot cast shadows. They commonly appear in regular, rippling patterns<ref name="H&H-340">{{harvnb|Hubbard|2000|p=340}}</ref> or in rows of clouds with clear areas between.<ref name="cloud-classification">{{cite web|last=Funk|first=Ted|title=Cloud Classifications and Characteristics|url=http://www.crh.noaa.gov/lmk/soo/docu/cloudchart.pdf|url-status=dead|archive-url=https://web.archive.org/web/20040720234037/http://www.crh.noaa.gov/lmk/soo/docu/cloudchart.pdf|archive-date=July 20, 2004|access-date=19 October 2012|work=The Science Corner|publisher=[[National Oceanic and Atmospheric Administration]]|page=1}}</ref> Cirrocumulus are, like other members of the cumuliform and stratocumuliform categories, formed via [[convection|convective]] processes.<ref name="parungo-251">{{harvnb|Parungo|1995|p=251}}</ref> Significant growth of these patches indicates high-altitude instability and can signal the approach of poorer weather.<ref name="common-clouds"/><ref name="audubon-448"/> The ice crystals in the bottoms of cirrocumulus clouds tend to be in the form of hexagonal cylinders. They are not solid, but instead tend to have stepped funnels coming in from the ends. Towards the top of the cloud, these crystals have a tendency to clump together.<ref name="parungo-252">{{harvnb|Parungo|1995|p=252}}</ref> These clouds do not last long, and they tend to change into cirrus because as the water vapor continues to deposit on the ice crystals, they eventually begin to fall, destroying the upward convection. The cloud then dissipates into cirrus.<ref name="parungo-254">{{harvnb|Parungo|1995|p=254}}</ref> Cirrocumulus clouds come in four species which are common to all three genus-types that have limited-convective or stratocumuliform characteristics: ''stratiformis'', ''lenticularis'', ''castellanus'', and ''floccus''.<ref name="common-clouds">{{cite web|title=Common Cloud Names, Shapes, and Altitudes|publisher=Georgia Institute of Technology|url=http://nenes.eas.gatech.edu/Cloud/Clouds.pdf|access-date=12 February 2011|pages=2, 10&ndash;13|archive-url=https://web.archive.org/web/20110512162814/http://nenes.eas.gatech.edu/Cloud/Clouds.pdf|archive-date=12 May 2011|url-status=dead}}</ref> They are [[iridescence|iridescent]] when the constituent supercooled water droplets are all about the same size.<ref name="audubon-448">{{harvnb|Ludlum|2000|p=448}}</ref>

=== Altocumulus clouds ===
[[File:Altocumulus stratiformis clouds-01.jpg|thumb|Altocumulus clouds]]
{{main article|Altocumulus cloud}}
Altocumulus clouds are a mid-level cloud that forms from {{convert|2000|m|ft}} high to {{convert|4000|m|ft}} in polar areas, {{convert|7000|m|ft}} in temperate areas, and {{convert|7600|m|ft}} in tropical areas.<ref name="nws-jetstream">{{cite web|title=Cloud Classifications|url=http://oceanservice.noaa.gov/education/yos/resource/JetStream/synoptic/clouds_max.htm|url-status=dead|archive-url=https://web.archive.org/web/20141107063301/http://oceanservice.noaa.gov/education/yos/resource/JetStream/synoptic/clouds_max.htm|archive-date=7 November 2014|access-date=21 July 2014|work=JetStream|publisher=National Weather Service}}</ref> They can have precipitation and are commonly composed of a mixture of ice crystals, supercooled water droplets, and water droplets in temperate latitudes. However, the liquid water concentration was almost always significantly greater than the concentration of ice crystals, and the maximum concentration of liquid water tended to be at the top of the cloud while the ice concentrated itself at the bottom.<ref name="Carey2490">{{harvnb|Carey et al.|2008|p=2490}}</ref><ref name="Carey2491">{{harvnb|Carey et al.|2008|p=2491}}</ref> The ice crystals in the base of the altocumulus clouds and in the virga were found to be dendrites or conglomerations of dendrites while needles and plates resided more towards the top.<ref name="Carey2491" /> Altocumulus clouds can form via convection or via the forced uplift caused by a [[warm front]].<ref name="Carey2494">{{harvnb|Carey et al.|2008|p=2494}}</ref>

=== Stratocumulus clouds ===
[[File:Flat Stratocumulus Cloud.jpg|thumb|Stratocumulus clouds]]
{{main article|Stratocumulus cloud}}
A stratocumulus cloud is another type of stratocumuliform cloud. Like cumulus clouds, they form at low levels<ref name="cloud-classification" /> and via convection. However, unlike cumulus clouds, their growth is almost completely retarded by a strong [[Inversion (meteorology)|inversion]]. As a result, they flatten out like stratus clouds, giving them a layered appearance. These clouds are extremely common, covering on average around twenty-three percent of the Earth's oceans and twelve percent of the Earth's continents. They are less common in tropical areas and commonly form after [[cold front]]s. Additionally, stratocumulus clouds reflect a large amount of the incoming sunlight, producing a net cooling effect.<ref name="Wood2374">{{harvnb|Wood|2012|p=2374}}</ref> Stratocumulus clouds can produce [[drizzle]], which stabilizes the cloud by warming it and reducing turbulent mixing.<ref name="Wood2398">{{harvnb|Wood|2012|p=2398}}</ref>

=== Cumulonimbus clouds ===
{{main article|Cumulonimbus cloud}}
Cumulonimbus clouds are the final form of growing cumulus clouds. They form when ''cumulus congestus'' clouds develop a strong [[updraft]] that propels their tops higher and higher into the atmosphere until they reach the [[tropopause]] at {{convert|18000|m|ft}} in altitude. Cumulonimbus clouds, commonly called thunderheads, can produce high winds, torrential rain, lightning, gust fronts, [[waterspout]]s, [[funnel cloud]]s, and tornadoes. They commonly have [[anvil cloud]]s.<ref name="TWC" /><ref name="cumulonimbus-incus" /><ref name="Ludlum471">{{harvnb|Ludlum|2000|p=471}}</ref>

=== Horseshoe clouds ===
{{main article|Horseshoe cloud}}
A short-lived [[horseshoe cloud]] may occur when a [[horseshoe vortex]] deforms a cumulus cloud.<ref name="IIE">{{cite web |title=An incredibly rare 'horseshoe cloud' was spotted in Nevada and it kept the meme-makers busy |url=https://www.independent.ie/world-news/and-finally/an-incredibly-rare-horseshoe-cloud-was-spotted-in-nevada-and-it-kept-the-mememakers-busy-36691086.html |website=Independent.ie |date=12 March 2018 |access-date=12 March 2018 }}</ref>

== Extraterrestrial ==
Some cumuliform and stratocumuliform clouds have been discovered on most other planets in the [[Solar System]]. On [[Mars]], the [[Viking Orbiter]] detected cirrocumulus and stratocumulus clouds forming via convection primarily near the polar icecaps.<ref name="Mars-clouds">{{cite web|url=https://history.nasa.gov/SP-441/ch12.htm|title=NASA SP-441: Viking Orbiter Views of Mars|publisher=National Aeronautics and Space Administration|access-date=26 January 2013}}</ref> The [[Galileo (spacecraft)|''Galileo'' space probe]] detected massive cumulonimbus clouds near the [[Great Red Spot]] on [[Jupiter]].<ref name="Jupiter-clouds">{{cite web|url=http://photojournal.jpl.nasa.gov/catalog/pia00506|title=Thunderheads on Jupiter|work=Jet Propulsion Laboratory|publisher=National Aeronautics and Space Administration|access-date=26 January 2013}}</ref> Cumuliform clouds have also been detected on [[Saturn]]. In 2008, the [[Cassini spacecraft|''Cassini'' spacecraft]] determined that cumulus clouds near Saturn's south pole were part of a cyclone over {{convert|4000|km|mi}} in diameter.<ref name="Saturn-clouds">{{cite news|last=Minard|first=Anne|date=14 October 2008|title=Mysterious Cyclones Seen at Both of Saturn's Poles|newspaper=National Geographic News|url=http://news.nationalgeographic.com/news/2008/10/081014-saturn-cyclones.html|url-status=dead|access-date=26 January 2013|archive-url=https://web.archive.org/web/20121123054759/http://news.nationalgeographic.com/news/2008/10/081014-saturn-cyclones.html|archive-date=23 November 2012}}</ref> The [[Keck Observatory]] detected whitish cumulus clouds on [[Uranus]].<ref name="Uranus-clouds">{{cite magazine|url=http://www.popsci.com/science/article/2012-10/most-richly-detailed-image-ever-taken-icy-distant-uranus|title=Check Out The Most Richly Detailed Image Ever Taken Of Uranus|magazine=Popular Science|last=Boyle|first=Rebecca|date=18 October 2012|access-date=26 January 2013}}</ref> Like Uranus, [[Neptune]] has methane cumulus clouds.<ref name="Irwin-115">{{harvnb|Irwin|2003|p=115}}</ref> [[Venus]], however, does not appear to have cumulus clouds.<ref name="Bougher-127-129">{{harvnb|Bougher|Phillips|1997|pp=127&ndash;129}}</ref>

== See also ==
{{Portal|Weather}}
*[[List of cloud types]]

== Notes ==
{{reflist|group=note}}

== References ==

=== Footnotes ===
{{reflist|30em}}

=== Bibliography ===
{{refbegin}}
*{{cite book|last1=Bougher|first1=Stephen Wesley|last2=Phillips|first2=Roger|title=Venus II: Geology, Geophysics, Atmosphere, and Solar Wind Environment|url=https://books.google.com/books?id=b93lEgkPquoC&pg=PA128|date= 1997|publisher=University of Arizona Press|isbn=978-0-8165-1830-2}}
*{{cite journal|author1=Carey, Lawrence D. |author2=Niu, Jianguo |author3=Yang, Ping |author4=Kankiewicz, J. Adam |author5=Larson, Vincent E. |author6=Haar, Thomas H. Vonder |date=September 2008|journal=Journal of Applied Meteorology and Climatology|title=The Vertical Profile of Liquid and Ice Water Content in Midlatitude Mixed-Phase Altocumulus Clouds|volume=47|issue=9|doi=10.1175/2008JAMC1885.1|pages=2487–2495 |ref=CITEREFCarey_et_al.2008 |bibcode=2008JApMC..47.2487C|doi-access=free}}
*{{cite journal|last1=Cho|first1=H. R.|last2=Iribarne|first2=J. V.|last3=Niewiadomski|first3=M.|last4=Melo |first4=O.|journal=Journal of Geophysical Research|date=20 September 1989|title=A Model of the Effect of Cumulus Clouds on the Redistribution and Transformation of Pollutants|volume=94|number=D10|pages=12,895–12,910|doi=10.1029/jd094id10p12895|bibcode=1989JGR....9412895C|url=http://www.grims-model.org/front/bbs/paper/mps-2/MPS_1989-3_Cho_et_al.pdf |archive-url=https://web.archive.org/web/20140814192437/http://www.grims-model.org/front/bbs/paper/mps-2/MPS_1989-3_Cho_et_al.pdf|url-status=dead|archive-date=14 August 2014|access-date=28 November 2012}}
*{{cite journal|last1=Del Genfo|first1=Anthony D.|last2=Lacis|first2=Andrew A.|last3=Ruedy|first3=Reto A.|title=Simulations of the effect of a warmer climate on atmospheric humidity|journal=Nature|volume=351 |pages=382–385 |doi=10.1038/351382a0|date=30 May 1991|issue=6325|bibcode=1991Natur.351..382G|s2cid=4274337 }}
*{{cite book|last=Dunlop|first=Storm|url=https://books.google.com/books?id=BR2ft4G5TgQC|title=The Weather Identification Handbook|date=June 2003|publisher=Lyons Press|isbn=978-1-58574-857-0}}
*{{cite journal|author1=Garrett, T. J. |author2=Dean-Day, J. |author3=Liu, C. |author4=Barnett, B. |author5=Mace, G. |author6=Baumgardner, D. |author7=Webster, C. |author8=Bui, T. |author9=Read, W. |author10=Minnis, P. |title=Convective formation of pileus cloud near the tropopause|journal=Atmospheric Chemistry and Physics|doi=10.5194/acp-6-1185-2006|volume=6|issue=5|pages=1185&ndash;1200|date=19 April 2006|bibcode=2006ACP.....6.1185G |ref=CITEREFGarrett_et_al.2006|doi-access=free |hdl=2060/20080015842 |hdl-access=free }}
*{{cite book|last1=Hubbard|first1=Richard Keith|title=Boater's Bowditch: The Small Craft American Practical Navigator|chapter-url=https://books.google.com/books?id=nfWSxRr8VP4C&pg=PA340 |edition=2nd |date=2000|publisher=International Marine/Ragged Mountain Press|isbn=978-0-07-136136-1|chapter=Glossary}}
*{{cite book|last=Irwin|first=Patrick|title=Giant Planets of Our Solar System: Atmospheres, Composition, and Structure|url=https://books.google.com/books?id=p8wCsJweUb0C&pg=PA115|isbn=978-3-540-00681-7|date=July 2003 |edition=1st |publisher=Springer|page=115}}
*{{cite journal|last=Junge|first=C. E.|title=Sulfur in the Atmosphere|year=1960|pages=227–237|volume=65 |number=1|doi=10.1029/JZ065i001p00227|journal=Journal of Geophysical Research|bibcode=1960JGR....65..227J}}
*{{cite journal|last=Langmuir|first=Irving|journal=Journal of Meteorology|title=The Production of Rain by a Chain Reaction in Cumulus Clouds at Temperatures Above Freezing|volume=5|issue=5|pages=175–192|date=October 1948 |doi=10.1175/1520-0469(1948)005<0175:TPORBA>2.0.CO;2|bibcode=1948JAtS....5..175L|doi-access=free}}
*{{cite book|title=National Audubon Society Field Guide to Weather|year=2000|publisher=Alfred A. Knopf |isbn=978-0-679-40851-2|oclc=56559729|last=Ludlum|first=David McWilliams|url-access=registration |url=https://archive.org/details/audubonsocietyfi00ludl}}
*{{cite book|last1=Miyazaki|first1=Ryo|last2=Yoshida|first2=Satoru|last3=Dobashi|first3=Yoshinori |last4=Nishita|first4=Tomoyula|title=Proceedings Ninth Pacific Conference on Computer Graphics and Applications. Pacific Graphics 2001|isbn=978-0-7695-1227-3|year=2001|doi=10.1109/PCCGA.2001.962893|page=363 |chapter=A method for modeling clouds based on atmospheric fluid dynamics|citeseerx=10.1.1.76.7428|s2cid=6656499 }}
*{{cite journal|last1=Mossop|first1=S. C.|last2=Hallett|first2=J.|title=Ice Crystal Concentration in Cumulus Clouds: Influence of the Drop Spectrum|volume=186|issue=4164|pages=632&ndash;634|date=November 1974|doi=10.1126/science.186.4164.632|journal=Science Magazine|bibcode=1974Sci...186..632M|pmid=17833720|s2cid=19285155 }}
*{{cite book|last=Pagen|first=Dennis|title=The Art of Paragliding|publisher=Black Mountain Books|year=2001|pages=105–108|isbn=978-0-936310-14-5}}
*{{cite journal|last=Parungo|title=Ice Crystals in High Clouds and Contrails|journal=Atmospheric Research|volume=38|issue=1|first=F.|oclc=90987092|doi=10.1016/0169-8095(94)00096-V|date=May 1995|pages=249–262|bibcode=1995AtmRe..38..249P}}
*{{cite book|last=Pretor-Pinney|first=Gavin|author-link=Gavin Pretor-Pinney|url=https://books.google.com/books?id=ix4qy7FihDcC|title=The Cloudspotter's Guide: The Science, History, and Culture of Clouds|isbn=978-1-101-20331-6|date=June 2007|publisher=Penguin Group}}
*{{cite journal|last=Stommel|first=Harry|doi=10.1175/1520-0469(1947)004<0091:EOAIAC>2.0.CO;2|title=Entrainment of Air Into a Cumulus Cloud|date=June 1947|journal=Journal of Meteorology|volume=4|issue=3|pages=91&ndash;94|bibcode=1947JAtS....4...91S|doi-access=free}}
*{{cite journal|last=Warner|first=J.|title=The Micro structure of Cumulus Cloud. Part I. General Features of the Droplet Spectrum|doi=10.1175/1520-0469(1969)026<1049:TMOCCP>2.0.CO;2|journal=Journal of the Atmospheric Sciences|date=September 1969|volume=26|issue=5|pages=1049–1059|bibcode=1969JAtS...26.1049W|doi-access=free}}
*{{cite journal|last=Weston|first=K. J.|title=An Observational Study of Convective Cloud Streets|doi=10.1111/j.2153-3490.1980.tb00970.x|date=October 1980|journal=Tell Us|volume=32|issue=35|pages=433&ndash;438|bibcode=1980Tell...32..433W}}
*{{cite journal|last=Wood|first=Robert|title=Stratocumulus Clouds|journal=Monthly Weather Review|doi=10.1175/MWR-D-11-00121.1|date=August 2012|volume=140|issue=8|pages=2373–2423|bibcode=2012MWRv..140.2373W|doi-access=free}}
{{refend}}

== External links ==
{{commons category|Cumulus clouds}}
* [http://glossary.ametsoc.org/wiki/Main_Page AMS Glossary of Meteorology]

{{Cloud types}}

{{Authority control}}

{{DEFAULTSORT:Cumulus Cloud}}
[[Category:Cumulus| ]]
[[Category:Cloud types]]
[[Category:Articles containing video clips]]