Castle Geyser erupts about every 12 hours and eruptions last for about 50 minutes. Water bursts went 60 feet into the air and helped push the clouds of steam hundreds of feet higher. Castle Geyser was in its steam phase just after sunrise. The climbing cloud of moisture created dynamic ephemeral shapes. Winter is a great time to observe thermals because the presence and motion of the hot water and steam is much more apparent in cold air.