Giant Geyser

Giant Geyser is a cone geyser in Yellowstone’s Upper Geyser Basin, near Old Faithful. It’s worth a look for its steaming mineral cone, even when it’s quiet; don’t plan your day around a major eruption. Boardwalks wind through the basin from the Old Faithful area, and interpretive information is listed at the geyser. Stay on the boardwalks and designated trails because hydrothermal water can severely burn.

When it erupts, Giant can send water up to 250 feet and keep going for more than an hour. Small geysers on the same platform may erupt before or during the main burst, so the whole platform can be active at once.

Giant became dormant in 1955, then returned to erratic activity. It erupted more than 50 times in 2007 and once in 2010. Those swings show why an old interval is no way to plan a visit; the eruption is a bonus, not a showtime.

Constrictions in underground plumbing hold back heated water and steam. Pressure builds until water forces its way past them, turning a hot spring into a geyser.

The pale mineral cone is the dependable sight. In a photo, include some of the dark trees behind it to bring out the cone’s shape and steaming vents; a tight crop of steam loses what makes Giant distinctive.