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<span id="openzim-page-title" class="mw-page-title-main"><span class="mw-page-title-main">Pyroclastic flow</span></span>

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<p>A <b>pyroclastic flow</b> (also known as a <b>pyroclastic density current</b> or a <b>pyroclastic cloud</b>)<sup id="cite_ref-1" class="reference"><a href="#cite_note-1"><span class="cite-bracket">[</span>1<span class="cite-bracket">]</span></a></sup> is a fast-moving current of hot <a href="Volcanic_gas" title="Volcanic gas">gas</a> and volcanic matter (collectively known as <a href="Tephra" title="Tephra">tephra</a>) that flows along the ground away from a <a href="Volcano" title="Volcano">volcano</a> at average speeds of 100 km/h (30 m/s; 60 mph) but is capable of reaching speeds up to 700 km/h (190 m/s; 430 mph).<sup id="cite_ref-2" class="reference"><a href="#cite_note-2"><span class="cite-bracket">[</span>2<span class="cite-bracket">]</span></a></sup> The gases and tephra can reach temperatures of about 1,000 °C (1,800 °F).

</p><p>Pyroclastic flows are the deadliest of all <a href="Volcanic_hazard" title="Volcanic hazard">volcanic hazards</a><sup id="cite_ref-3" class="reference"><a href="#cite_note-3"><span class="cite-bracket">[</span>3<span class="cite-bracket">]</span></a></sup> and are produced as a result of certain <a href="Explosive_eruptions" class="mw-redirect" title="Explosive eruptions">explosive eruptions</a>; they normally touch the ground and hurtle downhill or spread laterally under gravity. Their speed depends upon the density of the current, the volcanic output rate, and the gradient of the slope.

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<div class="mw-heading mw-heading2"><h2 id="Origin_of_term">Origin of term</h2></div>

<p>The word <i>pyroclast</i> is derived from the <a href="Greek_language" title="Greek language">Greek</a> <span title="Ancient Greek (to 1453)-language text"><span lang="grc"><a href="https://en.wiktionary.org/wiki/%CF%80%E1%BF%A6%CF%81" class="extiw external" title="wikt:πῦρ">πῦρ</a></span></span> (<i>pýr</i>), meaning "fire", and <span title="Ancient Greek (to 1453)-language text"><span lang="grc"><a href="https://en.wiktionary.org/wiki/%CE%BA%CE%BB%CE%B1%CF%83%CF%84%CF%8C%CF%82" class="extiw external" title="wikt:κλαστός">κλαστός</a></span></span> (<i>klastós</i>), meaning "broken in pieces".<sup id="cite_ref-4" class="reference"><a href="#cite_note-4"><span class="cite-bracket">[</span>4<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-PerseusDict_5-0" class="reference"><a href="#cite_note-PerseusDict-5"><span class="cite-bracket">[</span>5<span class="cite-bracket">]</span></a></sup> A name for pyroclastic flows that glow red in the dark is <b><span title="French-language text"><i lang="fr">nuée ardente</i></span></b> (French, "burning cloud"); this was notably used to describe the disastrous 1902 eruption of <a href="Mount_Pel%C3%A9e" title="Mount Pelée">Mount Pelée</a> on <a href="Martinique" title="Martinique">Martinique</a>, a French island in the Caribbean.<sup id="cite_ref-6" class="reference"><a href="#cite_note-6"><span class="cite-bracket">[</span>6<span class="cite-bracket">]</span></a></sup><sup id="cite_ref-7" class="reference"><a href="#cite_note-7"><span class="cite-bracket">[</span>note 1<span class="cite-bracket">]</span></a></sup>

</p><p>Pyroclastic flows that contain a much higher proportion of gas to rock are known as "fully dilute pyroclastic density currents" or <a href="Pyroclastic_surge" title="Pyroclastic surge">pyroclastic surges</a>. The lower density sometimes allows them to flow over higher topographic features or water such as ridges, hills, rivers, and seas. They may also contain steam, water, and rock at less than 250 °C (480 °F); these are called "cold" compared with other flows, although the temperature is still lethally high. Cold pyroclastic surges can occur when the eruption is from a vent under a shallow lake or the sea. Fronts of some pyroclastic density currents are fully dilute; for example, during the eruption of Mount Pelée in 1902, a fully dilute current overwhelmed the city of <a href="Saint-Pierre%2C_Martinique" title="Saint-Pierre, Martinique">Saint-Pierre</a> and killed nearly 30,000 people.<sup id="cite_ref-8" class="reference"><a href="#cite_note-8"><span class="cite-bracket">[</span>7<span class="cite-bracket">]</span></a></sup>

</p><p>A pyroclastic flow is a type of <a href="Gravity_current" title="Gravity current">gravity current</a>; in scientific literature, it is sometimes abbreviated to PDC (pyroclastic density current).

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<div class="mw-heading mw-heading2"><h2 id="Causes">Causes</h2></div>

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<p>Several mechanisms can produce a pyroclastic flow:

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<ul><li><i>Fountain collapse</i> of an <a href="Eruption_column" title="Eruption column">eruption column</a> from a <a href="Plinian_eruption" title="Plinian eruption">Plinian eruption</a> (e.g. <a href="Eruption_of_Mount_Vesuvius_in_79" class="mw-redirect" title="Eruption of Mount Vesuvius in 79">Mount Vesuvius' destruction of Herculaneum and Pompeii</a> in 79 AD). In such an eruption, the material forcefully ejected from the vent heats the surrounding air and the turbulent mixture rises, through <a href="Convection" title="Convection">convection</a>, for many kilometers. If the erupted jet is unable to heat the surrounding air sufficiently, convection currents will not be strong enough to carry the plume upwards and it falls, flowing down the flanks of the volcano.</li>

<li><i>Fountain collapse</i> of an eruption column associated with a <a href="Vulcanian_eruption" title="Vulcanian eruption">Vulcanian eruption</a> (e.g., <a href="Montserrat" title="Montserrat">Montserrat</a>'s <a href="Soufri%C3%A8re_Hills" title="Soufrière Hills">Soufrière Hills</a> volcano has generated many of these deadly pyroclastic flows and surges). The gas and projectiles create a cloud that is denser than the surrounding air and becomes a pyroclastic flow.</li>

<li>Frothing at the mouth of the vent during degassing of the erupted lava. This can lead to the production of a rock called <a href="Ignimbrite" title="Ignimbrite">ignimbrite</a>. This occurred during the eruption of <a href="Novarupta" title="Novarupta">Novarupta</a> in 1912.</li>

<li>Gravitational collapse of a <a href="Lava_dome" title="Lava dome">lava dome</a> or spine, with subsequent avalanches and flows down a steep slope (e.g., Montserrat's Soufrière Hills volcano, which caused nineteen deaths in 1997).</li>

<li>The <a href="Lateral_eruption" title="Lateral eruption">directional blast</a> (or jet) when part of a volcano collapses or explodes (e.g., the <a href="1980_eruption_of_Mount_St._Helens" title="1980 eruption of Mount St. Helens">eruption of Mount St. Helens on May 18, 1980</a>). As distance from the volcano increases, this rapidly transforms into a gravity-driven current.</li></ul>

<div class="mw-heading mw-heading2"><h2 id="Size_and_effects">Size and effects</h2></div>

<p>Flow volumes range from a few hundred cubic meters to more than 1,000 cubic kilometres (240 cu mi). Larger flows can travel for hundreds of kilometres, although none on that scale has occurred for several hundred thousand years. Most pyroclastic flows are around <style data-mw-deduplicate="TemplateStyles:r1154941027">

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</style>one to ten cubic kilometres (<span class="frac"><span class="num">1</span>⁄<span class="den">4</span></span>–<span class="frac">2<span class="sr-only">+</span><span class="num">1</span>⁄<span class="den">2</span></span> cu mi) and travel for several kilometres. Flows usually consist of two parts: the <i>basal flow</i> hugs the ground and contains larger, coarse boulders and rock fragments, while an extremely hot <a href="Ash_plume" class="mw-redirect" title="Ash plume">ash plume</a> lofts above it because of the turbulence between the flow and the overlying air, admixing and heating cold atmospheric air causing expansion and convection.<sup id="cite_ref-9" class="reference"><a href="#cite_note-9"><span class="cite-bracket">[</span>8<span class="cite-bracket">]</span></a></sup> Flows can deposit less than 1 meter to 200 meters in depth of loose rock fragment.<sup id="cite_ref-10" class="reference"><a href="#cite_note-10"><span class="cite-bracket">[</span>9<span class="cite-bracket">]</span></a></sup>

</p><p>The <a href="Kinetic_energy" title="Kinetic energy">kinetic energy</a> of the moving cloud will flatten trees and buildings in its path. The hot gases and high speed make them particularly lethal, as they will incinerate living organisms instantaneously or turn them into carbonized fossils:

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<ul><li>The <a href="Ancient_Rome" title="Ancient Rome">Ancient Roman</a> cities of <a href="Pompeii" title="Pompeii">Pompeii</a> and <a href="Herculaneum" title="Herculaneum">Herculaneum</a> (now in Italy), for example, were engulfed by pyroclastic surges of <a href="Mount_Vesuvius" title="Mount Vesuvius">Mount Vesuvius</a> in AD 79 with many lives lost.<sup id="cite_ref-11" class="reference"><a href="#cite_note-11"><span class="cite-bracket">[</span>10<span class="cite-bracket">]</span></a></sup></li>

<li>The 1902 eruption of <a href="Mount_Pel%C3%A9e" title="Mount Pelée">Mount Pelée</a> destroyed the <a href="Martinique" title="Martinique">Martinique</a> town of <a href="Saint-Pierre%2C_Martinique" title="Saint-Pierre, Martinique">St. Pierre</a>. Despite signs of impending eruption, the government deemed St. Pierre safe due to hills and valleys between it and the volcano, but the pyroclastic flow charred almost the entirety of the city, killing all but three of its 30,000 residents.</li>

<li>A pyroclastic surge killed <a href="Volcanologist" title="Volcanologist">volcanologists</a> <a href="Harry_Glicken" title="Harry Glicken">Harry Glicken</a> and <a href="Katia_and_Maurice_Krafft" title="Katia and Maurice Krafft">Katia and Maurice Krafft</a> and 40 other people on <a href="Mount_Unzen" title="Mount Unzen">Mount Unzen</a>, in Japan, on June 3, 1991. The surge started as a pyroclastic flow and the more energised surge climbed a spur on which the Kraffts and the others were standing; it engulfed them, and the corpses were covered with about 5 mm (<span class="frac"><span class="num">1</span>⁄<span class="den">4</span></span> in) of ash.<sup id="cite_ref-12" class="reference"><a href="#cite_note-12"><span class="cite-bracket">[</span>11<span class="cite-bracket">]</span></a></sup></li>

<li>On June 25, 1997, a pyroclastic flow travelled down Mosquito Ghaut on the <a href="Caribbean" title="Caribbean">Caribbean</a> island of <a href="Montserrat" title="Montserrat">Montserrat</a>. A large, highly energized pyroclastic surge developed. This flow could not be restrained by the Ghaut and spilled out of it, killing 19 people who were in the Streatham village area (which was officially evacuated). Several others in the area suffered severe burns.</li></ul>

<div class="mw-heading mw-heading3"><h3 id="Interaction_with_water">Interaction with water</h3></div>

<p>Testimonial evidence from the <a href="1883_eruption_of_Krakatoa" title="1883 eruption of Krakatoa">1883 eruption of Krakatoa</a>, supported by experimental evidence,<sup id="cite_ref-Freundt2003_13-0" class="reference"><a href="#cite_note-Freundt2003-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> shows that pyroclastic flows can cross significant bodies of water. However, that might be a <a href="Pyroclastic_surge" title="Pyroclastic surge">pyroclastic surge</a>, not flow, because the density of a gravity current means it cannot move across the surface of water.<sup id="cite_ref-Freundt2003_13-1" class="reference"><a href="#cite_note-Freundt2003-13"><span class="cite-bracket">[</span>12<span class="cite-bracket">]</span></a></sup> One flow reached the <a href="Sumatra" title="Sumatra">Sumatran</a> coast as far as 48 kilometres (26 nautical miles) away.<sup id="cite_ref-14" class="reference"><a href="#cite_note-14"><span class="cite-bracket">[</span>13<span class="cite-bracket">]</span></a></sup>

</p><p>A 2006 BBC documentary film, <i>Ten Things You Didn't Know About Volcanoes</i>,<sup id="cite_ref-15" class="reference"><a href="#cite_note-15"><span class="cite-bracket">[</span>14<span class="cite-bracket">]</span></a></sup> demonstrated tests by a research team at <a href="Kiel_University" title="Kiel University">Kiel University</a>, Germany, of pyroclastic flows moving over the water.<sup id="cite_ref-16" class="reference"><a href="#cite_note-16"><span class="cite-bracket">[</span>15<span class="cite-bracket">]</span></a></sup> When the reconstructed pyroclastic flow (stream of mostly hot ash with varying densities) hit the water, two things happened: the heavier material fell into the water, precipitating out from the pyroclastic flow and into the liquid; the temperature of the ash caused the water to evaporate, propelling the pyroclastic flow (now only consisting of the lighter material) along on a bed of steam at an even faster pace than before.

</p><p>During some phases of the Soufriere Hills volcano on Montserrat, pyroclastic flows were filmed about 1 km (<span class="frac"><span class="num">1</span>⁄<span class="den">2</span></span> nmi) offshore. These show the water boiling as the flow passes over it. The flows eventually built a delta, which covered about 1 km<sup>2</sup> (250 acres). Another example was observed in 2019 at <a href="Stromboli" title="Stromboli">Stromboli</a> when a pyroclastic flow traveled for several hundreds of meters above the sea.<sup id="cite_ref-17" class="reference"><a href="#cite_note-17"><span class="cite-bracket">[</span>16<span class="cite-bracket">]</span></a></sup>

</p><p>A pyroclastic flow can interact with a body of water to form a large amount of mud, which can then continue to flow downhill as a <a href="Lahar" title="Lahar">lahar</a>. This is one of several mechanisms that can create a lahar.

</p>

<div class="mw-heading mw-heading3"><h3 id="On_other_celestial_bodies">On other celestial bodies</h3></div>

<p>In 1963, NASA astronomer <a href="Winifred_Cameron" title="Winifred Cameron">Winifred Cameron</a> proposed that the lunar equivalent of terrestrial pyroclastic flows may have formed sinuous <a href="Rille" title="Rille">rilles</a> on the <a href="Moon" title="Moon">Moon</a>. In a lunar volcanic eruption, a pyroclastic cloud would follow local relief, resulting in an often sinuous track. The Moon's <a href="Schroter's_Valley" title="Schroter's Valley">Schröter's Valley</a> offers one example.<sup id="cite_ref-18" class="reference"><a href="#cite_note-18"><span class="cite-bracket">[</span>17<span class="cite-bracket">]</span></a></sup>

Some volcanoes on <a href="Mars" title="Mars">Mars</a>, such as <a href="Tyrrhenus_Mons" title="Tyrrhenus Mons">Tyrrhenus Mons</a> and <a href="Hadriacus_Mons" title="Hadriacus Mons">Hadriacus Mons</a>, have produced layered deposits that appear to be more easily eroded than lava flows, suggesting that they were emplaced by pyroclastic flows.<sup id="cite_ref-19" class="reference"><a href="#cite_note-19"><span class="cite-bracket">[</span>18<span class="cite-bracket">]</span></a></sup>

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<ul><li><a href="Pyroclastic_fall" title="Pyroclastic fall">Pyroclastic fall</a></li>

<li><a href="Pyroclastic_rock" title="Pyroclastic rock">Pyroclastic rock</a></li>

<li><a href="Welded_tuff" class="mw-redirect" title="Welded tuff">Welded tuff</a></li></ul>

<div class="mw-heading mw-heading2"><h2 id="References">References</h2></div>

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</style><cite id="CITEREFBranneyKokelaar2002" class="citation book cs1">Branney, Michael J.; Kokelaar, B. Peter (2002). <i>Pyroclastic Density Currents and the Sedimentation of Ignimbrites</i>. Geological Society of London. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-1-86239-124-6</bdi>.</cite></span>

</li>

<li id="cite_note-2"><span class="mw-cite-backlink"><b><a href="#cite_ref-2">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://pubs.usgs.gov/gip/msh//pyroclastic.html">"MSH Pyroclastic flow [USGS]"</a>. United States Geological Survey.</cite></span>

</li>

<li id="cite_note-3"><span class="mw-cite-backlink"><b><a href="#cite_ref-3">^</a></b></span> <span class="reference-text"><cite id="CITEREFAukerSparksSiebertCrosweller2013" class="citation journal cs1">Auker, Melanie Rose; Sparks, Robert Stephen John; Siebert, Lee; Crosweller, Helen Sian; Ewert, John (2013-02-14). <a rel="nofollow" class="external text" href="https://doi.org/10.1186%2F2191-5040-2-2">"A statistical analysis of the global historical volcanic fatalities record"</a>. <i>Journal of Applied Volcanology</i>. <b>2</b> (1): 2. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2013JApV....2....2A">2013JApV....2....2A</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<span class="id-lock-free" title="Freely accessible"><a rel="nofollow" class="external text" href="https://doi.org/10.1186%2F2191-5040-2-2">10.1186/2191-5040-2-2</a></span>. <a href="ISSN_(identifier)" class="mw-redirect" title="ISSN (identifier)">ISSN</a> <a rel="nofollow" class="external text" href="https://search.worldcat.org/issn/2191-5040">2191-5040</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:44008872">44008872</a>.</cite></span>

</li>

<li id="cite_note-4"><span class="mw-cite-backlink"><b><a href="#cite_ref-4">^</a></b></span> <span class="reference-text">See:

<ul><li><cite id="CITEREFJukes1862" class="citation book cs1">Jukes, Joseph Beete (1862). <a rel="nofollow" class="external text" href="https://archive.org/details/bub_gb_xExMQScTSSoC"><i>The Student's Manual of Geology</i></a> (2nd ed.). Edinburgh, Scotland, U.K.: <a href="Adam_and_Charles_Black" class="mw-redirect" title="Adam and Charles Black">Adam and Charles Black</a>. p. <a rel="nofollow" class="external text" href="https://archive.org/details/bub_gb_xExMQScTSSoC/page/n90">68</a>.</cite> From p. 68: "The word "ash" is not a very good one to include all the mechanical accompaniments of a subaerial or subaqueous eruption, since ash seems to be restricted to a fine powder, the residuum of combustion. A word is wanting to express all such accompaniments, no matter what their size or condition may be, when they are accumulated in such mass as to form beds of "rock." We might call them perhaps "pyroclastic materials," … "</li></ul>

</span></li>

<li id="cite_note-PerseusDict-5"><span class="mw-cite-backlink"><b><a href="#cite_ref-PerseusDict_5-0">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.perseus.tufts.edu/hopper/morph?l=klasto%2Fs&la=greek&can=klasto%2Fs0">"Definition of κλαστός"</a>. <i>Perseus Greek Dictionary</i>. <a href="Tufts_University" title="Tufts University">Tufts University</a><span class="reference-accessdate">. Retrieved <span class="nowrap">8 October</span> 2020</span>.</cite></span>

</li>

<li id="cite_note-6"><span class="mw-cite-backlink"><b><a href="#cite_ref-6">^</a></b></span> <span class="reference-text">Lacroix, A. (1904) <i>La Montagne Pelée et ses Eruptions</i>, Paris, Masson (in French) <a rel="nofollow" class="external text" href="https://books.google.com/books?id=eh0hAQAAMAAJ&pg=PA38">From vol. 1, p. 38:</a> After describing on p. 37 the eruption of a "dense, black cloud" (<i>nuée noire</i>), Lacroix coins the term <span title="French-language text"><i lang="fr">nuée ardente</i></span>: "<span title="French-language text"><i lang="fr">Peu après l'éruption de ce que j'appellerai désormais la <strong>nuée ardente</strong>, un immense nuage de cendres couvrait l'ile tout entière, la saupoudrant d'une mince couche de débris volcaniques.</i></span>" (Shortly after the eruption of what I will call henceforth the <i>dense, glowing cloud</i> [<i>nuée ardente</i>], an immense cloud of cinders covered the entire island, sprinkling it with a thin layer of volcanic debris.)</span>

</li>

<li id="cite_note-8"><span class="mw-cite-backlink"><b><a href="#cite_ref-8">^</a></b></span> <span class="reference-text">Arthur N. Strahler (1972), <i>Planet Earth: its physical systems through geological time</i></span>

</li>

<li id="cite_note-9"><span class="mw-cite-backlink"><b><a href="#cite_ref-9">^</a></b></span> <span class="reference-text">Myers and Brantley (1995). Volcano Hazards Fact Sheet: Hazardous Phenomena at Volcanoes, USGS Open File Report 95-231</span>

</li>

<li id="cite_note-10"><span class="mw-cite-backlink"><b><a href="#cite_ref-10">^</a></b></span> <span class="reference-text"><cite class="citation web cs1"><a rel="nofollow" class="external text" href="https://www.usgs.gov/programs/VHP/pyroclastic-flows-move-fast-and-destroy-everything-their-path">"Pyroclastic flows move fast and destroy everything in their path | U.S. Geological Survey"</a>. United States Geological Survey<span class="reference-accessdate">. Retrieved <span class="nowrap">2024-09-12</span></span>.</cite></span>

</li>

<li id="cite_note-11"><span class="mw-cite-backlink"><b><a href="#cite_ref-11">^</a></b></span> <span class="reference-text"><cite id="CITEREFWeller2005" class="citation book cs1">Weller, Roger (2005). <a rel="nofollow" class="external text" href="https://web.archive.org/web/20101023185623/http://skywalker.cochise.edu/wellerr/students/mount-vesuvius2/vesuvius.htm"><i>Mount Vesuvius, Italy</i></a>. Cochise College Department of Geology. Archived from <a rel="nofollow" class="external text" href="http://skywalker.cochise.edu/wellerr/students/mount-vesuvius2/vesuvius.htm">the original</a> on 23 October 2010<span class="reference-accessdate">. Retrieved <span class="nowrap">15 October</span> 2010</span>.</cite></span>

</li>

<li id="cite_note-12"><span class="mw-cite-backlink"><b><a href="#cite_ref-12">^</a></b></span> <span class="reference-text">Sutherland, Lin. Reader's Digest Pathfinders Earthquakes and Volcanoes. New York: Weldon Owen Publishing, 2000.</span>

</li>

<li id="cite_note-Freundt2003-13"><span class="mw-cite-backlink">^ <a href="#cite_ref-Freundt2003_13-0"><sup><i><b>a</b></i></sup></a> <a href="#cite_ref-Freundt2003_13-1"><sup><i><b>b</b></i></sup></a></span> <span class="reference-text"><cite id="CITEREFFreundt2003" class="citation journal cs1">Freundt, Armin (2003). "Entrance of hot pyroclastic flows into the sea: experimental observations". <i><a href="Bulletin_of_Volcanology" title="Bulletin of Volcanology">Bulletin of Volcanology</a></i>. <b>65</b> (2): <span class="nowrap">144–</span>164. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/2002BVol...65..144F">2002BVol...65..144F</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1007%2Fs00445-002-0250-1">10.1007/s00445-002-0250-1</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:73620085">73620085</a>.</cite></span>

</li>

<li id="cite_note-14"><span class="mw-cite-backlink"><b><a href="#cite_ref-14">^</a></b></span> <span class="reference-text">Camp, Vic. "KRAKATAU, INDONESIA (1883)". How Volcanoes Work. Department of Geological Sciences, San Diego State University, 31 Mar. 2006. Web. 15 Oct. 2010. <a rel="nofollow" class="external autonumber" href="http://www.geology.sdsu.edu/how_volcanoes_work/Krakatau.html">[1]</a> <a rel="nofollow" class="external text" href="https://web.archive.org/web/20141216203501/http://www.geology.sdsu.edu/how_volcanoes_work/Krakatau.html">Archived</a> 2014-12-16 at the <a href="Wayback_Machine" title="Wayback Machine">Wayback Machine</a>.</span>

</li>

<li id="cite_note-15"><span class="mw-cite-backlink"><b><a href="#cite_ref-15">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="https://www.imdb.com/title/tt1027751/"><i>Ten Things You Didn't Know About Volcanoes (2006)</i></a> at <a href="IMDb_(identifier)" class="mw-redirect" title="IMDb (identifier)">IMDb</a></span>

</li>

<li id="cite_note-16"><span class="mw-cite-backlink"><b><a href="#cite_ref-16">^</a></b></span> <span class="reference-text"><a rel="nofollow" class="external text" href="http://cat.inist.fr/?aModele=afficheN&cpsidt=14575991">Entrance of hot pyroclastic flows into the sea: experimental observations</a>, <a href="INIST" class="mw-redirect" title="INIST">INIST</a>.</span>

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<li id="cite_note-17"><span class="mw-cite-backlink"><b><a href="#cite_ref-17">^</a></b></span> <span class="reference-text"><cite id="CITEREFde_VitaDi_VitoNave2019" class="citation web cs1 cs1-prop-foreign-lang-source">de Vita, Sandro; Di Vito, Mauro A.; Nave, Rosella (2019-09-05). <a rel="nofollow" class="external text" href="https://ingvvulcani.com/2019/09/05/quando-un-flusso-piroclastico-scorre-sul-mare-esempi-a-stromboli-e-altri-vulcani/">"Quando un flusso piroclastico scorre sul mare: esempi a Stromboli e altri vulcani"</a>. <i>INGV vulcani</i> (in Italian)<span class="reference-accessdate">. Retrieved <span class="nowrap">2021-10-04</span></span>.</cite></span>

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<cite id="CITEREFCameron1964" class="citation journal cs1">Cameron, W. S. (1964). "An Interpretation of Schröter's Valley and Other Lunar Sinuous Rills". <i><a href="Journal_of_Geophysical_Research" title="Journal of Geophysical Research">Journal of Geophysical Research</a></i>. <b>69</b> (12): <span class="nowrap">2423–</span>2430. <a href="Bibcode_(identifier)" class="mw-redirect" title="Bibcode (identifier)">Bibcode</a>:<a rel="nofollow" class="external text" href="https://ui.adsabs.harvard.edu/abs/1964JGR....69.2423C">1964JGR....69.2423C</a>. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1029%2FJZ069i012p02423">10.1029/JZ069i012p02423</a>.</cite></span>

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<li id="cite_note-19"><span class="mw-cite-backlink"><b><a href="#cite_ref-19">^</a></b></span> <span class="reference-text"><cite id="CITEREFZimbelmanGarryBleacherCrown2015" class="citation book cs1">Zimbelman, James R.; Garry, William Brent; Bleacher, Jacob Elvin; Crown, David A. (2015). <a rel="nofollow" class="external text" href="https://www.sciencedirect.com/science/article/pii/B9780123859389000419">"Volcanism on Mars"</a>. In Sigurdsson, Haraldur; Houghton, Bruce; McNutt, Steve; Rymer, Hazel; Stix, John (eds.). <i>The Encyclopedia of Volcanoes</i> (Second ed.). Amsterdam: Zimbelman. pp. <span class="nowrap">717–</span>728. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>978-0-12-385938-9</bdi>.</cite></span>

</li>

</ol></div></div>

<ul><li>Sigurdson, Haraldur: Encyclopedia of volcanoes. Academic Press, 546–548. <a href="ISBN_(identifier)" class="mw-redirect" title="ISBN (identifier)">ISBN</a> <bdi>0-12-643140-X</bdi>.</li></ul>

<div class="mw-heading mw-heading2"><h2 id="Notes">Notes</h2></div>

<li id="cite_note-7"><span class="mw-cite-backlink"><b><a href="#cite_ref-7">^</a></b></span> <span class="reference-text">Although the coining of the term <span title="French-language text"><i lang="fr">nuée ardente</i></span> in 1904 is attributed to the French geologist <a href="Alfred_Lacroix" title="Alfred Lacroix">Antoine Lacroix</a>, according to:

<ul><li><cite id="CITEREFHooker1965" class="citation journal cs1">Hooker, Marjorie (1965). "The origin of the volcanological concept <i>nuée ardente</i>". <i>Isis</i>. <b>56</b> (4): <span class="nowrap">401–</span>407. <a href="Doi_(identifier)" class="mw-redirect" title="Doi (identifier)">doi</a>:<a rel="nofollow" class="external text" href="https://doi.org/10.1086%2F350041">10.1086/350041</a>. <a href="S2CID_(identifier)" class="mw-redirect" title="S2CID (identifier)">S2CID</a> <a rel="nofollow" class="external text" href="https://api.semanticscholar.org/CorpusID:144772310">144772310</a>.</cite></li></ul>

the term was used in 1873 by Lacroix's father-in-law and former professor, French geologist <a href="Ferdinand_Andr%C3%A9_Fouqu%C3%A9" title="Ferdinand André Fouqué">Ferdinand André Fouqué</a> in his description of the 1580 and 1808 eruptions of the volcano on the island of <a href="S%C3%A3o_Jorge_Island" title="São Jorge Island">São Jorge</a> in the <a href="Azores" title="Azores">Azores</a>.

<ul><li><cite id="CITEREFFouqué1873" class="citation journal cs1 cs1-prop-foreign-lang-source">Fouqué, Ferdinand (1873). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=wOmW-ihiBZAC&pg=PA1198">"San Jorge et ses éruptions"</a> [São Jorge and its eruptions]. <i>Revue Scientifique de la France et de l'Étranger</i>. 2nd series (in French). <b>2</b> (51): <span class="nowrap">1198–</span>1201.</cite></li></ul>

<dl><dd><ul><li>From p. 1199: "<span title="French-language text"><i lang="fr">Un des phénomènes les plus singuliers de cette grande éruption est la production de ce que les témoins contemporains ont appelé des <strong>nuées ardentes</strong>.</i></span>" (One of the strangest phenomena of this great eruption is the production of what contemporary witnesses called <i>nuées ardentes</i>.)</li>

<li>From p. 1200: "<span title="French-language text"><i lang="fr">Les détonations cessent dans la journée du 17, mais alors apparaissent des <strong>nuées ardents</strong> semblables à celles de l'éruption de 1580.</i></span>" (The detonations cease on the day of the 17th, but then [there] appear burning clouds [<i>nuées ardents</i>] similar to those of the eruption of 1580.)</li></ul></dd></dl>

Marjorie Hooker – (Hooker, 1965), p. 405 – records that Father João Inácio da Silveira (1767–1852) from the village of Santo Amaro on São Jorge island wrote an account of the 1808 eruption in which he described an <span title="Portuguese-language text"><i lang="pt">ardente nuven</i></span> ("burning cloud" in Portuguese) that flowed down the slopes of the volcano. Silveira's account was published in 1871 and republished in 1883.

<ul><li><cite id="CITEREFSilveira1883" class="citation book cs1 cs1-prop-foreign-lang-source">Silveira, João Inácio da (1883). "XXVIII. Anno de 1808. Erupção na ilha de S. Jorge [XXVIII. Year of 1808. Eruption on the island of São Jorge.]". In Canto, Ernesto do (ed.). <a rel="nofollow" class="external text" href="https://books.google.com/books?id=WBMrAQAAMAAJ&pg=PA440"><i>Archivo dos Açores [Archive of the Azores]</i></a> (in Portuguese). Ponta Delgada, São Miguel, Azores: Archivo dos Açores. pp. <span class="nowrap">437–</span>441.</cite> From pp. 439–440: "<span title="Portuguese-language text"><i lang="pt">Em desassete do dito mês de Maio … de repente se levantou um tufão de fogo ou vulcão e introduzindo-se nas terras lavradias levantou todos aqueles campos até abaixo às vinhas com todas as árvores e bardos, fazendo-se uma medonha e <strong>ardente nuvem</strong> e correndo até abaixo de igreja queimou trinta e tantas pessoas na igreja e nos campos…</i></span>" (On the seventeenth of the said month of May … suddenly there arose a typhoon of fire out of the volcano and [it] entered the farm lands, heaved up all those fields down to the vineyards, with all the trees and hedges, forming a fearsome and burning cloud [<i>ardente nuvem</i>] and running down to the church, burned more than thirty people in the church and in the fields…)</li></ul>

</span></li>

</ol></div></div>

<div class="mw-heading mw-heading2"><h2 id="External_links">External links</h2></div>

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<ul><li><a rel="nofollow" class="external text" href="https://web.archive.org/web/20120323141226/http://www.maniacworld.com/erupting-volcano.htm">Pyroclastic Flows</a> video</li></ul>

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<ul><li><a href="Caldera" title="Caldera">Caldera</a></li>

<li><a href="Cinder_cone" title="Cinder cone">Cinder cone</a></li>

<li><a href="Complex_volcano" title="Complex volcano">Complex volcano</a></li>

<li><a href="Cryovolcano" title="Cryovolcano">Cryovolcano</a></li>

<li><a href="Cryptoexplosion" title="Cryptoexplosion">Cryptovolcanic structure</a></li>

<li><a href="Fissure_vent" title="Fissure vent">Fissure vent</a></li>

<li><a href="Mud_volcano" title="Mud volcano">Mud volcano</a></li>

<li><a href="Parasitic_cone" title="Parasitic cone">Parasitic cone</a></li>

<li><a href="Pyroclastic_cone" class="mw-redirect" title="Pyroclastic cone">Pyroclastic cone</a></li>

<li><a href="Pyroclastic_shield" title="Pyroclastic shield">Pyroclastic shield</a></li>

<li><a href="Rootless_cone" title="Rootless cone">Rootless cone</a></li>

<li><a href="Shield_volcano" title="Shield volcano">Shield volcano</a></li>

<li><a href="Somma_volcano" title="Somma volcano">Somma volcano</a></li>

<li><a href="Stratovolcano" title="Stratovolcano">Stratovolcano</a></li>

<li><a href="Subglacial_volcano" title="Subglacial volcano">Subglacial volcano</a></li>

<li><a href="Submarine_volcano" title="Submarine volcano">Submarine volcano</a></li>

<li><a href="Supervolcano" title="Supervolcano">Supervolcano</a></li>

<li><a href="Tossol" title="Tossol">Tossol</a></li>

<li><a href="Volcanic_cone" title="Volcanic cone">Volcanic cone</a></li>

<li><a href="Harmonic_tremor" title="Harmonic tremor">Harmonic tremor</a></li></ul>

</div></td><td class="noviewer navbox-image" rowspan="3" style="width:1px;padding:0 0 0 2px"><div><span typeof="mw:File"></span></div></td></tr><tr><th scope="row" class="navbox-group" style="text-align:center;;width:1%"><a href="Volcanic_rock" title="Volcanic rock">Volcanic rocks</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Agglomerate" title="Agglomerate">Agglomerate</a></li>

<li><a href="Andesite" title="Andesite">Andesite</a></li>

<li><a href="Basalt" title="Basalt">Basalt</a></li>

<li><a href="Basaltic_andesite" title="Basaltic andesite">Basaltic andesite</a></li>

<li><a href="Benmoreite" title="Benmoreite">Benmoreite</a></li>

<li><a href="Blairmorite" title="Blairmorite">Blairmorite</a></li>

<li><a href="Scoria" title="Scoria">Cinder</a></li>

<li><a href="Dacite" title="Dacite">Dacite</a></li>

<li><a href="Felsite" title="Felsite">Felsite</a></li>

<li><a href="Ignimbrite" title="Ignimbrite">Ignimbrite</a></li>

<li><a href="Komatiite" title="Komatiite">Komatiite</a></li>

<li><a href="Lapilli" title="Lapilli">Lapilli</a></li>

<li><a href="Latite" title="Latite">Latite</a></li>

<li><a href="Leucitite" title="Leucitite">Leucitite</a></li>

<li><a href="Nephelinite" title="Nephelinite">Nephelinite</a></li>

<li><a href="Obsidian" title="Obsidian">Obsidian</a></li>

<li><a href="Phonolite" title="Phonolite">Phonolite</a></li>

<li><a href="Phonotephrite" title="Phonotephrite">Phonotephrite</a></li>

<li><a href="Pumice" title="Pumice">Pumice</a></li>

<li><a href="Rhyodacite" title="Rhyodacite">Rhyodacite</a></li>

<li><a href="Rhyolite" title="Rhyolite">Rhyolite</a></li>

<li><a href="Tephra" title="Tephra">Tephra</a></li>

<li><a href="Tephriphonolite" title="Tephriphonolite">Tephriphonolite</a></li>

<li><a href="Trachyandesite" title="Trachyandesite">Trachyandesite</a></li>

<li><a href="Trachybasalt" title="Trachybasalt">Trachybasalt</a></li>

<li><a href="Trachyte" title="Trachyte">Trachyte</a></li>

<li><a href="Pyroclastic_fall" title="Pyroclastic fall">Pyroclastic fall</a></li>

</ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="text-align:center;;width:1%">Lists and groups</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Hotspot_(geology)" title="Hotspot (geology)">Hotspot</a></li>

<li><a href="Lists_of_volcanoes" title="Lists of volcanoes">Lists of volcanoes</a></li>

<li><a href="List_of_volcanic_eruptions_by_death_toll" title="List of volcanic eruptions by death toll">Eruptions by death toll</a></li>

<li><a href="Decade_Volcanoes" title="Decade Volcanoes">Decade Volcanoes</a></li>

<li><a href="Volcanic_arc" title="Volcanic arc">Volcanic arc</a></li>

<li><a href="Volcanic_belt" title="Volcanic belt">Volcanic belt</a></li>

<li><a href="Volcanic_field" title="Volcanic field">Volcanic field</a>

<ul><li><a href="Monogenetic_volcanic_field" title="Monogenetic volcanic field">monogenetic</a></li>

<li><a href="Polygenetic_volcanic_field" title="Polygenetic volcanic field">polygenetic</a></li></ul></li></ul>

</div></td></tr><tr><td class="navbox-abovebelow" colspan="3" style="text-align:center;"><div>

<ul><li><span class="noviewer" typeof="mw:File"><span title="Category"></span></span> <b>Category</b></li>

<li><span class="noviewer" typeof="mw:File"><span title="Commons page"></span></span> <b><a href="https://commons.wikimedia.org/wiki/Category:Volcanoes" class="extiw external" title="commons:Category:Volcanoes">Commons</a></b></li>

<li><span class="noviewer" typeof="mw:File"></span> <b><a href="Portal%3AVolcanoes" title="Portal:Volcanoes">Portal</a></b></li>

<li><span class="noviewer" typeof="mw:File"><span title="WikiProject"></span></span> <b>WikiProject</b></li></ul>

</div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="Types_of_volcanic_eruptions120" style="padding:3px"><table class="nowraplinks mw-collapsible expanded navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Types_of_volcanic_eruptions120" style="font-size:114%;margin:0 4em">Types of <a href="Volcanic_eruption" title="Volcanic eruption">volcanic eruptions</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Magma" title="Magma">Magmatic</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Hawaiian_eruption" title="Hawaiian eruption">Hawaiian</a></li>

<li><a href="Pel%C3%A9an_eruption" title="Peléan eruption">Peléan</a></li>

<li><a href="Plinian_eruption" title="Plinian eruption">Plinian</a></li>

<li><a href="Strombolian_eruption" title="Strombolian eruption">Strombolian</a></li>

<li><a href="Vulcanian_eruption" title="Vulcanian eruption">Vulcanian</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Phreatomagmatic_eruption" title="Phreatomagmatic eruption">Phreatomagmatic</a></th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Subglacial_eruption" title="Subglacial eruption">Subglacial</a></li>

<li><a href="Submarine_eruption" title="Submarine eruption">Submarine</a></li>

<li><a href="Surtseyan_eruption" title="Surtseyan eruption">Surtseyan</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Phreatic" title="Phreatic">Phreatic</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Phreatic_eruption" title="Phreatic eruption">Phreatic</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other classifications</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Effusive_eruption" title="Effusive eruption">Effusive</a></li>

<li><a href="Explosive_eruption" title="Explosive eruption">Explosive</a></li>

<li><a href="Flank_eruption" title="Flank eruption">Flank</a></li>

<li><a href="Lateral_eruption" title="Lateral eruption">Lateral</a></li>

<li><a href="Limnic_eruption" title="Limnic eruption">Limnic</a></li>

<li><a href="Subaerial_eruption" title="Subaerial eruption">Subaerial</a></li></ul>

</div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="Magmatic_processes78" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2" style="background: #FFBF00;"><div id="Magmatic_processes78" style="font-size:114%;margin:0 4em"><a href="Magma" title="Magma">Magmatic processes</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%;background: #FFBF00;">Components of magma</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Liquid_phase" class="mw-redirect" title="Liquid phase">Liquid phase</a></li>

<li><a href="Igneous_mineral" class="mw-redirect" title="Igneous mineral">Igneous rocks</a></li>

<li>Dissolved and exolved <a href="Gas" title="Gas">gases</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background: #FFBF00;">Processes</th><td class="navbox-list-with-group navbox-list navbox-even hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Fractional_crystallization_(geology)" title="Fractional crystallization (geology)">Fractional crystallization</a></li>

<li><a href="Igneous_differentiation#Assimilation" title="Igneous differentiation">Assimilation</a></li>

<li><a href="Igneous_differentiation#Magma_mixing" title="Igneous differentiation">Magma mixing</a></li>

<li>Magma mingling</li>

<li><a href="Exsolution" class="mw-redirect" title="Exsolution">Exsolution</a> of gases</li>

<li><a href="Outgassing" title="Outgassing">Outgassing</a></li>

<li><a href="Partial_melting" title="Partial melting">Partial melting</a></li>

<li><a href="Anorogenic_magmatism" title="Anorogenic magmatism">Anorogenic magmatism</a></li>

<li><a href="Flux_melting" title="Flux melting">Flux melting</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%;background: #FFBF00;">Surface manifestations</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Igneous_rock" title="Igneous rock">Igneous rock</a></li>

<li><a href="Geothermal_systems" class="mw-redirect" title="Geothermal systems">Geothermal systems</a></li>

<li><a href="Geothermal_gradient" title="Geothermal gradient">Geothermal gradient</a> anomalies</li>

<li><a href="Volcanism" title="Volcanism">Volcanism</a></li></ul>

</div></td></tr></tbody></table></div>

<div class="navbox-styles"></div><div role="navigation" class="navbox" aria-labelledby="Natural_disasters_–_list_by_death_toll158" style="padding:3px"><table class="nowraplinks mw-collapsible autocollapse navbox-inner" style="border-spacing:0;background:transparent;color:inherit"><tbody><tr><th scope="col" class="navbox-title" colspan="2"><div id="Natural_disasters_–_list_by_death_toll158" style="font-size:114%;margin:0 4em"><a href="Natural_disaster" title="Natural disaster">Natural disasters</a> – <a href="List_of_natural_disasters_by_death_toll" title="List of natural disasters by death toll">list by death toll</a></div></th></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Geological_hazard" title="Geological hazard">Geological</a></th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Mass_wasting" title="Mass wasting">Mass wasting</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Landslide" title="Landslide">Landslide</a></li>

<li><a href="Avalanche" title="Avalanche">Avalanche</a></li>

<li><a href="Mudflow" title="Mudflow">Mudflow</a></li>

<li><a href="Debris_flow" title="Debris flow">Debris flow</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Earthquake" title="Earthquake">Earthquake</a><br>(<a href="Lists_of_earthquakes" title="Lists of earthquakes">List</a>)</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Seismic_hazard" title="Seismic hazard">Seismic hazard</a></li>

<li><a href="Seismic_risk" title="Seismic risk">Seismic risk</a></li>

<li><a href="Soil_liquefaction" title="Soil liquefaction">Soil liquefaction</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Types_of_volcanic_eruptions" class="mw-redirect" title="Types of volcanic eruptions">Volcano eruption</a></th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Lahar" title="Lahar">Lahar</a></li></ul></li>

<li><a href="Volcanic_ash" title="Volcanic ash">Volcanic ash</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Erosion" title="Erosion">Natural erosion</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Sinkhole" title="Sinkhole">Sinkhole</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Hydrological</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Flood" title="Flood">Flood</a><br>(<a href="List_of_floods" title="List of floods">List</a>)</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Coastal_flood" class="mw-redirect" title="Coastal flood">Coastal flood</a></li>

<li><a href="Flash_flood" title="Flash flood">Flash flood</a></li>

<li><a href="Storm_surge" title="Storm surge">Storm surge</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Other</th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Tsunami" title="Tsunami">Tsunami</a>

<ul><li><a href="Megatsunami" title="Megatsunami">Megatsunami</a></li></ul></li>

<li><a href="Limnic_eruption" title="Limnic eruption">Limnic eruption</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Meteorological</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em"></div><table class="nowraplinks navbox-subgroup" style="border-spacing:0"><tbody><tr><th scope="row" class="navbox-group" style="width:1%">Temperature</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Blizzard" title="Blizzard">Blizzard</a></li>

<li><a href="Ice_storm" title="Ice storm">Ice storm</a></li>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%"><a href="Drought" title="Drought">Drought</a></th><td class="navbox-list-with-group navbox-list navbox-even" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Megadrought" title="Megadrought">Megadrought</a></li></ul>

</div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Cyclonic storms</th><td class="navbox-list-with-group navbox-list navbox-odd" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Bomb_cyclone" class="mw-redirect" title="Bomb cyclone">Bomb cyclone</a></li>

<li><a href="Thunderstorm" title="Thunderstorm">Thunderstorm</a> (<a href="Hail" title="Hail">Hail</a>)</li>

<li><a href="Tornado" title="Tornado">Tornado</a> (<a href="Tornado_outbreak" title="Tornado outbreak">Tornado outbreak</a>)</li>

<li><a href="Tropical_cyclone" title="Tropical cyclone">Tropical cyclone</a></li></ul>

<ul><li><a href="Derecho" title="Derecho">Derecho</a></li>

<li><a href="Wildfire" title="Wildfire">Wildfire</a>

<ul><li><a href="Firestorm" title="Firestorm">Firestorm</a></li></ul></li>

<li><a href="ARkStorm" title="ARkStorm">ARkStorm</a></li></ul>

</div></td></tr></tbody></table><div></div></td></tr><tr><th scope="row" class="navbox-group" style="width:1%">Astronomical</th><td class="navbox-list-with-group navbox-list navbox-odd hlist" style="width:100%;padding:0"><div style="padding:0 0.25em">

<ul><li><a href="Potentially_hazardous_object" title="Potentially hazardous object">Potentially hazardous object</a></li>

<li><a href="Impact_event" title="Impact event">Impact event</a></li>

<li><a href="Meteor_shower" title="Meteor shower">Meteor shower</a></li>

<li><a href="Geomagnetic_storm" title="Geomagnetic storm">Geomagnetic storm</a></li>

<li><a href="Solar_flare" title="Solar flare">Solar flare</a></li>

<li><a href="Supernova" title="Supernova">Supernova</a></li>

<li><a href="Hypernova" title="Hypernova">Hypernova</a></li></ul>

</div></td></tr></tbody></table></div></div><div><div class="zim-footer">

This article is issued from <a class="external text" title="Last edited on 2025-04-18" href="https://en.wikipedia.org/wiki/?title=Pyroclastic_flow&oldid=1286244975">Wikipedia</a>. The text is available under <a class="external text" href="https://creativecommons.org/licenses/by-sa/4.0/deed.en">Creative Commons Attribution-Share Alike 4.0</a> unless otherwise noted. Additional terms may apply for the media files.

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