After coming to life earlier this week, the 8,26-foot-high Pavlov volcano is still erupting, with the Alaska Volcano Observatory noting "fire fountaining" at its summit Thursday, CNN reported.
A resulting cloud of ash and gas moved southeast over the Gulf of Alaska, reaching an altitude of about 20,000 feet above sea level.
That resulted in the National Weather Service issuing a "Significant Meterological Event" warning, called a SIGMET, to alert pilots of the hazardous conditions in the area.
Pavlof is "one of the most historically active volcanoes in the Northern Hemisphere," U.S. Geological Survey scientists John Power said.
Located on the Alaska Peninsula about 30 miles northeast of the community of King Cove, the Pavlof volcano last erupted in 2007.