Double Rainbow at Riverside Geyser, Yellowstone Poster

"Double Rainbow at Riverside Geyser, Yellowstone National Park, Vertical" by Catherine Sherman. An erupting geyser meets vibrant double rainbows under a partly cloudy sky during the eruption of Riverside Geyser in Yellowstone National Park, Wyoming. Tall evergreen trees stand in the background, creating a serene and picturesque natural scene. Riverside Geyser is located on the Firehole River within the Upper Geyser Basin. The geyser shoots steam and water to heights of 75 feet (23 meters) in an arch over the river, sometimes causing rainbows. The eruptions occur every 51⁄2 to 7 hours. As is Old Faithful, Riverside is one of the most predictable geysers in the park, because it is not located near any other geysers that may disrupt the flow of underground water in the geyser's plumbing. Sixty percent of the world's geysers are in Yellowstone National Park. The geysers of the Upper Basin in Yellowstone National Park represent the most concentrated group in the world - more than 250 are found in an area just two miles across. The majority of those are in a narrow band along both sides the Firehole River. There are five distinct geyser groups, beginning in the south at Old Faithful and nearby Geyser Hill. Two more groups are at Black Sand Basin, alongside Iron Spring Creek, and Biscuit Basin in the north, which is also along the Firehole River but more separated from the main region.