Yellowstone 2009 - April Photo

Biscuit Basin

Rust-colored algae accentuate the warm overflow from Sapphire Pool in Biscuit Basin. Sapphire became a large active geyser after the 1959 earthquake. It erupted regularly with bursts 125 to 150 feet high. As time passed, the geyser activity subsided and now it just boils. The run off from the bubbling blue pool drains into the Firehole River.