New vocabulary for me—not for Skus, with geography/geology background. It’s on a roadside point-of-interest sign on Highway 395 near Mono Lake, California, explaining the origin of the Long Valley Caldera.
Definition from thefreedictionary.com: nuée ardente Plural nuées ardentes: A fast moving gaseous cloud of hot ashes and other material thrown out from an erupting volcano. Nuées ardentes are often incandescent.
Now I have to find out what “incandescent” means in this context. I only know it as the kind of light bulb fast becoming old-fashioned. Google tells me: “emitting light as a result of being heated: ‘plumes of incandescent liquid rock’.”
Now I’m guessing the French means “silver cloud,” or maybe not: I think “argent” is silver, so this would be related to “ardent” and refer to its energy instead of its color.