Grand Geyser

Grand Geyser erupting in Yellowstone's Upper Geyser Basin
Going from left to right, from the rainbow in the above picture, you see Vent Geyser (jetting water and steam in front of the rainbow), Turban Geyser (a small splashing geyser in the picture's center), and Grand Geyser the main attraction.

Grand Geyser is in the Upper Geyser Basin north of Old Faithful Geyser. Grand Geyser puts on a fantastic show with its neighbors, Turban and Vent Geysers, and is a must-see whenever you are in the Old Faithful area.

Like Old Faithful Geyser, there is seating for you to wait for and watch the eruption. This area lacks shade and can get extremely hot during the summer. You should carry plenty of water for everyone in your party and drink while you wait. That wait can be considerable, depending on the current window. Your wait may be 2-4 hours. That said, it is absolutely worth the wait, but planning is encouraged.

Grand Geyser pool and Turban Geyser
It is easy to come to the area of Grand Geyser and think the mound of Turban Geyser is Grand. But no, Grand is the seemingly insignificant pool of water on the right. Once Grand erupts, you will experience a phenomenal show of nature.
Grand Geyser erupting from north of the geyser.
Walking up on a Grand Geyser eruption from deeper in the basin.

Grand Geyser is a fountain-type geyser, the most common type in Yellowstone. A fountain-type geyser erupts from a pool, typically has no cone, and splashes water and steam rather than sending up jets of water.

Grand Geyser is one of only six predicted geysers in the park.

Grand Geyser has a long interval, the time from the start of the last eruption to the beginning of the current eruption. Over the last several years, the interval has ranged from 6 to 7.5 hours. The window was between 45 minutes and 2 hours on either side of the predicted time. Yes, timing can change sometimes several times in the season as rangers monitor and adjust times to ensure as many visitors as possible can see this wonder of Yellowstone.

Predictable geysers appear to have separate plumbing systems from those around them, so their behavior is not affected by other geysers. But remember, it is only a prediction, not a guarantee.

Many geysers have pre-eruption indicators or preplay activity. One of Grand's pre-eruption indicators is the Turban Geyser. Turban Geyser is the most apparent geyser at Grand's location. Turban Geyser is higher than Grand's pool. Turban erupts every 17-25 minutes and splashes for about 5 minutes each time. When Turban erupts, the water level in Grand's pool will drop. During one eruption of Turban Grand's pool, the water level doesn't appear to fall. Then, you probably will see a ripple of waves in Grand's pool, which usually signals Grand's forthcoming eruption. That said, Grand has erupted without a Turban occasionally, and Grand doesn't always erupt when you see "waves on Grand."

Turban Geyser
Turban Geyser in eruption. The Turban Geyser will erupt every 17-25 minutes. Eventually, Grand will erupt, usually following the start of a Turban eruption.
Vent and Turban Geysers continuing to erupt after Grand has stopped erupting.
Grand Geyser has completed its eruption. Vent Geyser and Turban Geyser will continue to erupt for another 45-60 minutes.

Vent Geyser is on the left shoulder of Turban Geyser. Vent Geyser will start once Grand's eruption begins and can send water 70 feet into the air, settling to about 35 feet. After Grand Geyser stops erupting, Vent and Turban Geysers will continue to erupt for about the next hour.

Grand is different from all the other predicted geysers. Grand eruptions involve both fountain- and cone-type geysers.

To complicate a prediction of Grand Geyser are Rift and West Triplet Geysers, which are to the right of Grand. If either of those erupts, the Grand Geyser prediction will be modified and delayed by one hour.

Grand Geyser is a burst geyser, meaning it can erupt multiple times. In contrast, Old Faithful reaches its maximum height only once in an eruption. Grand can erupt over 100 feet on the first burst, lasting 8-12 minutes, and up to 200 feet or more on subsequent bursts, which are shorter in duration. Grand Geyser is considered the tallest predicted geyser in the world.

A Grand burst can have multiple splashes of water. A burst ends when the water drains, exposing the rocks in the basin. If Grand’s pool refills rapidly after the first burst, there may be another burst that reaches higher heights. Most eruptions of Grand Geyser are single bursts. A 1983 eruption had a mind-blowing 11 bursts!

Grand Geyser in Eruption
Grand in its glory. Grand is a burst geyser, meaning it can erupt multiple times during a single eruption with a short break between bursts. Once it stops, never leave until you don't see water refilling the basin.