A lava dome continues to grow in Mount Cleveland’s crater.

The Alaska Volcano Observatory raised Cleveland’s aviation color code to orange last Wednesday, and the volcano’s lava flow has grown 30 feet in the past week. Because there is no seismic monitoring equipment on the Aleutian volcano, AVO’s advisory is based on satellite data.

Last week, AVO geophysicist Dave Schneider told the Alaska Public Radio Network that the observatory would like to have better data on Cleveland, but that it would be “an extremely costly operation” to install and maintain monitoring equipment.

“The priority up to this point has been volcanos that are nearer to population centers and infrastructure,” says Schneider.

Mount Cleveland lies approximately 150 miles west of Unalaska. The volcano last erupted in 2008, and affected air travel in the region.