Columbia Pool is a beautiful azure blue pool named by the 1878 Hayden Expedition. Because of its remote location, Columbia Pool still retains much of its pristine condition. Large ledges, formed by white sinter deposits in the shape of rosettes, project over the pool. The size of the pool and the stability of the edge is deceiving. There are no boardwalks through this area and much of the Heart Lake Geyser Basin has very unstable ground.
Caution is advised.
Orange and yellow cyanobacteria surround the pool creating a beautiful display of color. On the slopes above Heart Lake and the Rustic Group, along Witch Creek, are the four remaining groups which make up the Heart Lake Basin. In these groups are numerous sulfur vents. The small vents, ranging within a few inches in size, are fumaroles. They do not possess enough water in their craters to become hot springs, but below the surface, water boils.