Steamboat Geyser

Yellowstone National Park's Upper Geyser Basin in June of 2006.
Yellowstone National Park

Last week, Yellowstone National Park saw thermal activity that hasn't been recorded in the area in decades.

Yellowstone Park's Ear Spring erupts, September 15, 2018.
Yellowstone National Park

Yellowstone National Park is reporting new thermal activity, including a rare eruption of Ear Spring.

The activity is in Upper Geyser Basin, on the other side of the Firehole River from Old Faithful.

Yellowstone Park's Steamboat Geyser during a 2004 eruption.

YELLOWSTONE NATIONAL PARK, Wyo. (AP) — The world's largest active geyser has erupted again in Yellowstone National Park.

The U.S. Geological Survey says the Steamboat Geyser erupted early Sunday, its fifth eruption this year.

The world's largest active geyser has erupted three times in the past two months at Yellowstone National Park, leaving scientists puzzled by the sudden and relatively frequent explosions.

A screen capture from a video shot by Yellowstone Park geologists, Friday, March 16, 2018 shows a steam plume from Steamboat Geyser.
Yellowstone National Park

Geologists believe the tallest geyser in the world erupted last week in Yellowstone National Park.

When it blows, Steamboat Geyser can send water and debris three times higher than Old Faithful, which park officials think it did last Thursday.