This photograph shows an eruption of Echinus Geyser as it looked in the early 1990's before it slowed down and weakened.

Echinus was a favorite of most park visitors. It is a fountain type geyser. Water is thrown from the pool in distinct bursts. You can never tell how big or in what direction a bust will go. In the early 1990's Bursts reached over 75 feet, up to 125 feet. You were close enough that you could get wet. But there was no need to worry, the water cooled as it flew through the air. The character of Echinus' eruptions is totally different from that of Old Faithful. This and observers close proximity to the eruption made it a real crowd pleaser.

Unfortunately, Echinus slowed down, weakened and became erratic in the late 1990's. Throughout the history of the park, it has been known to drastically change its strength and frequency. It is interesting to see one of these changes in progress.

Echinus is the largest acid geyser in the world. The water is about as acidic as lemon juice. Acid geysers are very rare. The vast majority are located at Norris.

This picture is from the Welcome to Yellowstone National Park!