Magnificent, surreal and ethereal, Grand Prismatic Spring is not only one of the most iconic thermal features in Yellowstone National Park, but also a stained-glass-window into the forces at work beneath the park’s surface. At 370 feet across and 120 feet deep, Grand Prismatic is the park’s largest hot spring. The boiling water of the spring is supplied by centuries old rainfall that has percolated down into the auqifer beneath the park and then heated by magma from a “hot spot” just a few miles (as little as 3-8) beneath the surface. The kaliedoscope of colors in the spring is created by heat-loving organisms called thermophiles – bacteria that are able to live at extremely high temperatures. Different bacteria thrive at different temperatures, explaining the rainbow of colors as the water in the spring cools as it flows out towards the edges. Not much survives in the center of the spring – where the temperature reaches 189 degrees Fahrenheit, and the color is a clear blue.
In all seasons, Grand Prismatic Spring captivates us. You can visit the Spring via boardwalk at Midway Geyser Basin on the Madison-Old Faithful Road. You can also view it from above by walking about a mile from the Fairy Falls Trailhead to an overlook.
“Nothing ever conceived by human art could equal the peculiar vividness and delicacy of color of these remarkable prismatic springs. Life becomes a privilege and a blessing after one has seen and thoroughly felt these incomparable types of nature’s cunning skill,” said Yellowstone explorer Ferdinand Hayden wrote of Grand Prismatic Spring in 1871. We agree.
If you are as fascinated by Yellowstone’s thermal features as we are, you can find out more here.
Photos: Jenny Golding & George Bumann