An explosion shook Cleveland Volcano in the east-central Aleutian Islands at 8:17 local time Tuesday morning.
It’s the volcano’s first explosion since November.
Kristi Wallace with the Alaska Volcano Observatory in Anchorage called it “a small, discrete, short-duration event.”
“We aren’t certain whether or not a significant ash cloud was produced, likely not, mostly because it was short duration,” she said.
Clouds blocked the satellite view of the volcano Tuesday morning, and scientists haven’t received any reports from local pilots yet.
Grant Aviation said its flights in the area have been grounded because of fog.
The National Weather Service has put out an alert on the possibility of an ash cloud heading to the north and east, likely below 20,000 feet altitude.
The Alaska Volcano Observatory has raised the alert level for the volcano from yellow to orange, meaning an eruption is underway with only minor ash emissions.
“This is pretty common for this volcano,” Wallace said. “Typically, you have one explosion and maybe nothing for months. Sometimes we have maybe a couple over a week-long period. So we’ll just wait and see.”
Since its last major eruption in 2001, Cleveland Volcano has been active occasionally, with small lava flows and ash clouds generally staying below 20,000 feet. Eruptions in 2001 sent ash clouds, which can threaten airplanes that encounter them, as high as 39,000 feet above sea level.
Cleveland Volcano is on uninhabited Chuginadak Island, about 45 miles west of the village of Nikolski, 150 miles southwest of Unalaska and 940 miles southwest of Anchorage.
The volcanic cone towers 5,676 feet above the Bering Sea.