Areas of the United States that once were covered by volcanic ash from Yellowstone's giant eruptions

Figures and pictures used with permission from "Windows into the Earth, The Geologic Story of Yellowstone and Grand Teton National Park", Robert B. Smith and Lee J. Siegel, Oxford University Press, 2000.

Map showing the area of the US that was once covered by ash from Yellowstone eruptions.

Figure 3. Areas of the United States that once were covered by volcanic ash from Yellowstone's giant eruptions 2 million and 630,000 years ago, compared with ashfall from the 760,000-year-old Long Valley caldera eruptions at Mammoth Lakes, California, and the 1980 eruption of Mount St. Helens, Washington. (Adapted from Sarna-Wojcicki, 1991.)