Scientists have increased the threat level of Alaska’s Cleveland Volcano from yellow to orange.
The Alaska Volcano Observatory says the volcano appears to have kicked up to an elevated unrest. In the past six days, three brief explosions from Cleveland Volcano were detected.
The color designation indicates that sudden explosions could send ash above 20,000 feet, threatening international air carriers.
Cleveland is not monitored with seismic instruments. Observatory officials say minor ash plumes were observed in satellite data after two of the explosions. The height of the plumes is not known.
The volcano is located on an uninhabited island in the Aleutian Islands.
Last May the volcano experienced a low-level eruption. Cleveland’s last significant eruption before that began in February 2011.