Geologists are on alert after the Cleveland Volcano spewed an ash plume up to 20,000 feet.

The Alaska Volcano Observatory reports that the volcano on Alaska's Aleutians Islands erupted late Friday, prompting the observatory to raise the mountain's threat level to code orange.

The observatory says satellite views showed the ash cloud drift northeast about 375 miles and disperse over the Bering Sea.

Cleveland is about 940 miles southwest of Anchorage, on a remote and uninhabited island.

The observatory says the 5,676-foot volcano's last significant eruption began in February 2001 and eventually produced a lava flow that reached the ocean.

It says ash emissions from Cleveland were most recently seen in June.