Grand Geyser is located north of Old Faithful Geyser in the Upper Geyser Basin. Grand Geyser puts on a fantastic show with its neighbor Turban and Vent Geysers and is definitely a must see whenever you are in the Old Faithful area. Going from left to right from the rainbow in the above picture you see: Vent Geyser (jetting water and steam up in front of rainbow), Turban Geyser (small splashing geyser in the picture's center, and Grand Geyser.
|Grand Geyser is a fountain-type geyser, the most common type of geyser in Yellowstone.. A fountain-type of geyser erupts from a pool, has no cone formation around it, and splashes the water and steam instead of sending up jets of water.|
|Grand Geyser is one of only six predicted geysers in the Park. Grand Geyser erupts approximately every 7.5 hours, but has a plus or minus 1.5 hours window on either side of the predicted time. Those geysers are able to be predicted because they have separate plumbing systems from other geysers around them, so their behavior is not affected by other geysers. But, remember it is only a prediction not a guarentee.|
|Many geysers have pre-eruption indicators or preplay activity. One of Grand's pre-eruption indicators is Turban Geyser. Turban Geyser is the most obvious geyser at Grand's location. Turban sets higher than Grand's pool. Turban erupts every 17 - 22 minutes and splashes for about 5 minutes each time. When Turban is erupting the water level in Grand's pool will drop. During one eruption of Turban Grand's pool water level doesn't appear to drop. Then you will see a ripple of waves on Grand's pool which usually signals Grand's forthcoming eruption.|
|Grand can erupt up to a height of 100 feet on the first burst and up to 200 feet or more with following bursts. Grand eruptions can have multiple burst of water. Meaning the geyser erupts once and goes through it cycle but if the pool refills rapidly after the first burst stand by because it will have another burst that can go to the higher heights. Most eruptions of Grand Geyser are single bursts.|
|Vent Geyser sets to the left of Turban Geyser. Once Grand's eruption starts Vent Geyser will start and can send water 70 feet in the air that settles down to about 35 feet. After Grand stops erupting Vent and Turban Geysers will continue to erupt for the next hour or so.|