Castle Geyser

Castle Geyser has the largest cone and may be the oldest of all geysers in the basin. Its eruption pattern has changed considerably throughout its recorded history. Castle is currently erupting about every 10 - 12 hours. A water eruption frequently reaches 90 feet (27m) and lasts about 20 minutes. The water phase is followed by a noisy steam phase lasting 30 - 40 minutes.

Source: National Park Service