Grand Prismatic Spring Overlook

Yellowstone National Parkas newest trail offers a unique vantage point of the colorful Grand Prismatic Spring. The trail was constructed to protect resources and visitors while alleviating traffic around the Midway Geyser Basin. The trail begins from the Fairy Falls Trailhead. Hikers cross a bridge over the Firehole River and walk along a wide crushed-gravel trail. At the first junction, the trail swings left and gently climbs up through new lodgepole growth. Arrive at a large viewing platform. The platform is surrounded by a rail, making this a great hike for the young ones. Take in the clear view over Grand Prismatic Spring and Excelsior Geyser. The temperature of Grand Prismatic ranges from 145 degrees to 188 degrees, with the highest temperature at the center in the clear blue waters. Just off center, at a temperature of 165 degrees, the synechococcus bacterium becomes predominant as noted by the greenish color. Calothrix and Phormidium are cyanobacteria that form the respective dark brown and orange bacterial mats around the outer rim of the spring. Blue steam rises from Excelsior Geyser Crater just past Grand Prismatic. Excelsior was once one of the worldas largest geysers, but its last major eruptions were in the 1880s. Members of Montana Conservation Corps and Youth Conservation Corps designed and built the overlook trail. They also rehabilitated numerous unofficial social trails formed by visitors who went off-trail and scrambled up the slope.