Alaska's remote Cleveland volcano is growing restless again, according to the Alaska Volcano Observatory.

Satellite images have detected elevated surface temperatures on Cleveland's summit for the past week, and a light dusting of ash was visible in an image taken Sunday, the agency wrote on its website.

"The volcano has entered a renewed period of unrest," AVO reported, prompting the agency to raise its alert level to advisory and its aviation code to yellow.

The increased temperatures are "consistent with renewed growth of the small lava dome within the summit crater," and "the possibility of sudden explosions has increased," AVO said.

Roughly 940 miles southwest of Anchorage, the volcano forms the west part of uninhabited Chuginadak Island in the east-central Aleutian chain.

Cleveland is one of Alaska's most active volcanoes and has been in a near-constant state of eruption since 2006, AVO geologist Tina Neal told Alaska Dispatch News in September.