Over the past few weeks, the lava level has been rising inside the massive Halema‘uma‘u Crater of Hawaii’s Kilauea volcano. On Sunday, the volcano put on a spectacular show for Big Island tourists when a portion of the crater collapsed into the lava lake.

As the crater wall fell into the lake of molten earth, it exploded into gas and rocks the size of a fist, which were deposited on the crater rim.

Janet Babb of the U.S. Geological Survey likens the lava explosion to uncorking a bottle of champagne. “You look at the bottle and you see the liquid, but you don’t see the gas,” Babb told the Associated Press. “There’s a lot of gas in the lava. And so, when that rock fall hits the lava lake, it’s like the moment you knock the top of the champagne bottle off and that gas is released and it hurls molten lava and rock fragments.”

Babb says the explosion of gas and rock fragments reached a height of 280 feet. The Hawaiian Volcano Observatory says this is a relatively “small explosive event” on the scale of typical volcanic activity.

The Halema‘uma‘u Crater, which surrounds the lava lake, is actually embedded within the main Kilauea crater on the Big Island of Hawaii. All three features are visible from the visitor center of Hawai’i Volcanoes National Park, and tend to be the highlight for tourists. Usually, the attraction is the plume of gas that is nearly constantly streaming from the lava lake, along with the dazzling orange glow that the lava casts upon the clouds.

But the lake level has risen to a record height, and the lava has actually been visible from the visitor center overlook. On April 29, the lava rose so high that it spilled onto the Halema‘uma‘u Crater floor.

The USGS says that park visitors are witnessing Hawaii volcano history. “Because of the high lava lake level, visitors at the Jaggar Museum Overlook in Hawai’i Volcanoes National Park can, for the first time since the Kīlauea summit eruption began in March 2008, see the actual lake surface, as well as molten lava spattering above the vent rim,” the Hawaiian Volcano Observatory writes.