Even when inactive, Excelsior still produces a huge runoff, approximately 4500 gallons per minute or 6 million gallons per day. Flood Geyser is a fountain-type geyser. Erupting with bursts to 25 feet at intervals of minutes to a few hours. At times though, Flood has been known to have intervals of 2-3 hours with durations of only about five minutes. The geyser is located at the base of the hill on the edge of the Firehole River.
Flood actually has a fairly large crater.
The distance and the large size of its nearby neighbor, Circle Pool, conspire to make it look small. Flood erupts from a circular crater approximately 30 feet in diameter. Between eruptions, the water in Flood sits down a few feet. As the eruption nears, boiling in the crater begins. The boiling increases and then the water quickly rises and Flood bursts to life.