nuée ardente

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nuée ardente A French phrase, meaning ‘glowing cloud’, first used in 1903 by Alfred Lacroix (1863–1948) to describe the complete phenomenon of a basal pyroclastic flow and its overriding ash cloud formed by the collapse of a volcanic dome. Since the pyroclastic flow and ash cloud behave differently from one another during transport and produce contrasting deposits, volcanologists now tend to avoid using the term.