An explosion at one of Alaska's most active volcanoes has led scientists to raise its alert level from "advisory" to "watch."
Cleveland Volcano is located on an uninhabited island in the central Aleutians. On Monday afternoon, the Alaska Volcano Observatory detected a short-lived explosion that was also heard by residents of Nikolski, 45 miles away.
Chris Waythomas is a geologist with the observatory, and he said this is common behavior for the often-restless volcano.
"Think of Cleveland as the classic champagne cork coming out," he said. "Lava accumulates in the summit crater, it tends to pressurize, and then occasionally that lava cap gets exploded out — just like a cork coming out of a bottle."
Despite the lava, Waythomas said there was no sign of a larger ash cloud, although overcast skies made it difficult to see the summit during the explosion.
"Since then, the volcano has been quiet," he said. "We've had a few clear web camera views of the summit, and there was a very small steam — and possibly ash — plume in the crater, but it's not going any place."
That means it's possible Cleveland will erupt or explode again, but not necessarily likely.
Waythomas said the observatory will keep the volcano's alert level at "watch" until the activity dies off.