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EarthWord – Nuée Ardente

February 1, 2016

A nuée ardente is a turbulent, fast moving cloud of hot gas and ash erupted from a volcano. 

EarthWords is an on-going series in which we shed some light on the complicated, often difficult-to-pronounce language of science. Think of us as your terminology tour-guides, and meet us back here every week for a new word!

Pyroclastic flows descend the south eastern flank of Mayon Volcano, Philippines, during its 1984 eruption
Pyroclastic flows descend the south eastern flank of Mayon Volcano,Philippines, during its 1984 eruption. Credit: USGS


  • A nuée ardente is a turbulent, fast moving cloud of hot gas and ash erupted from a volcano. They form during explosive eruptions as columns of erupted material collapse or during non-explosive eruptions when volcanic rock collapses. Nuées ardentes (pl) flow downslope into valleys at speeds that often exceed 50 mph and temperatures of 400 to 1300 O F. They spread laterally, travel near the ground, and are often accompanied by larger rocks and boulders from the eruption. These materials collectively are better known as pyroclastic flows, and the term nuée ardente is now considered outdated.


  • Nuée ardente is French for “glowing cloud.” The name reflects the fiery red and orange colors that are sometimes visible during an eruption. The term was coined by a French geologist observing the eruption of Mount Pelée on the island of Martinique in 1902. While it is now considered outdated, if you travel to the West Indies you still may hear it used.

Use/Significance in the Earth Science Community:

  • Pyroclastic flows are very dangerous due to their speed, temperatures, and tendency to travel near the ground. They can engulf victims within seconds. Escape on foot or by vehicle is nearly impossible, and they can incinerate nearly anything in their path. People outside the destroyed area can suffer burn injuries or asphyxia from inhaling hot toxic gasses and ash. Pyroclastic flows are behind many of the deadliest eruptions on record. These facts have prompted earth scientists worldwide to seek tools that can provide early clues on pending eruptions and enable evacuations in advance.


  • USGS provides scientific research to better understand volcanoes and limit the losses that they can inflict. Efforts include monitoring volcanoes with modern instruments and remote sensing for early signs of activity, studying past eruptions, assessing volcano hazards, developing partnerships with and issuing warnings to emergency managers, airplane pilots , news media, and the public. Direct notifications are available to anyone through the USGS volcano notification service.
  • A slideshow of USGS maps showing zones for a variety of volcano hazards is available for Cascade Range volcanoes. More information on hazards at these and other U.S. volcanoes is available on the “find a volcano” dropdown menu.
  • USGS also works with partners worldwide in response to volcanic crises. This work benefits the host country and helps USGS scientists to learn more about volcanoes in new settings and under extreme circumstances.  

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