The Cleveland Volcano in the Aleutian Islands is again under a heightened alert level from the Alaska Volcano Observatory, after researchers there recorded an explosion Thursday evening. The observatory issued a statement raising the eastern Aleutians volcano’s alert level to watch, and its aviation color code to orange, late Thursday. Researchers said in the statement they detected an explosion at 6:44 p.m. Thursday using both air pressure and seismic data.

“There are no recent satellite views since the detected explosion. However, previous Cleveland explosions have typically produced ash emissions,” observatory staff wrote. Nearly a year ago, scientists recorded a restless period at the volcano on Chuginadak Island, including an explosion — but no detected ash cloud — in July. READ MORE