When in major phase eruptions steamboat can erupt as high as 380 feet. Its height of between 300 and 400 feet make it the highest currently erupting geyser. It has a 3 to 20 minute water phase followed by a prolonged steam phase, which can last for more than 12 hours. Major eruption are highly erratic, and unpredictable. Interval of 3 days to over 50 years have been known.
Steamboat has long periods when it only has minor eruptions.
It has occasional periods when it is almost entirely dormant. See photos of the steam phase of the eruption at the Yellowstone Association News Release Page . Beautiful photo of Steamboat in Steam-prone later stages of its eruption. This was the last recorded eruption of Steamboat. It has been quiet since then.