The world's tallest active geyser, Steamboat can erupt to more than 300 feet (90m), showering viewers with its mineral-rich waters. For hours following its rare 3 to 40 minute major eruptions, Steamboat thunders with powerful jets of steam.

The magnitude and destructive force of a major eruption of Steamboat Geyser are unforgettable. Water intermittently surges from two vents to varying heights. Suddenly water explodes from the larger north vent more than 300 feet high.

Curtains of water fall to the slope above the geyser and collect in torrents rushing back into the vent, carrying huge amounts of mud, sand, and rock that are shot skyward again and again. Water coats everything with a glistening layer of silica. Trees and cars in the parking lot are often covered with eruption debris, including silica water and rocks.

The water phase of a major eruption lasts from 3 minutes to more than 40 minutes. Once the water supply is exhausted, the geyser continues with a powerful steam phase lasting from several hours to a day and a half. Its roar is so great that conversation near the geyser is difficult, and visitors in the Norris Campground, a mile to the north, have been awakened by the noise.

Cistern Spring, at the base of the hill, exhibits changes related to its gigantic neighbor. After 1959, Cistern Spring's temperature gradually rose, possibly receiving some of this heat from Steamboat. Cistern began increasing discharge in 1965 when Steamboat's frequency of major eruptions was beginning to decrease.

This surge in heat and water was so great that all vegetation immediately south of Cistern was killed and a colorful silica terrace rapidly grew several feet high. This terrace continues to rise and expand. Since that time, Cistern has also drained after a major Steamboat eruption.

As befitting such an awesome event, full eruptions are entirely unpredictable. In recent years, Steamboat has had several major eruptions. More commonly, Steamboat has minor eruptions and ejects water in frequent bursts of 10 to 40 feet.

In Yellowstone National Park's recorded history, only two other geysers, Excelsior Geyser and Sapphire Pool, have exceeded Steamboat in massiveness. Both of these geysers are currently inactice.

Information provided by the National Park Service.