Nature’s Forces

Shaping a Monumental Landscape

Yellowstone’s geyser basins, such as Old Faithful, and hot springs point to the presence of molten rock not far, in a geologist’s view, below the surface. Other forces of nature are powerfully in evidence—mountain-forming upheavals, glaciers, and wildfires that scorch and revitalize natural systems. Snowmelt from Yellowstone’s high country becomes streams that wind through volcanic terrain to feed the Snake, Missouri, and Green Rivers.


“Yellowstone is an enormous volcano, which is difficult to see if you're looking for the familiar cone shape. In the past 2.5 million years, two of the largest volcanic eruptions known on Earth happened here. The most recent of these formed the Yellowstone Caldera, the depression where most of the park's 10,000-plus geothermal features are found. Earthquakes and other ground movements remind us that this volcano is still very much alive.”

—Jacob Lowenstern, Yellowstone Volcano Observatory scientist-in-charge, Yellowstone National Park

“Springtime flooding along streams and rivers renews some of the most productive and diverse natural systems in the west—home to river otter, native trout, songbirds, and a long list of other animals. Rivers shaped the social landscape, too. These natural passageways attracted explorers, farmers, miners, and settlers to their banks. Look at the region’s major communities and you’ll likely find rivers flowing through.”

—Ken Sinay, owner/guide, Yellowstone Safari, Livingston, MT

the best travel advice comes from the people who live here
Tim O'Donoghue