Shishaldin Volcano had an eruption Friday morning that produced an ash cloud approximately 24,000 feet and volcanic lightning.
Matt Haney, a geophysicist with the Alaska Volcano Observatory, said the volcano – located about 58 miles southwest of Cold Bay – has been active since July.
"Shishaldin has been in an eruptive state for the past few months," said Haney. "It's been having lava flows that have been spreading out on the north side of the volcano. But interspersed with those lava flows have been these periods of explosive eruptive activity."
Haney said the main hazard from an eruption at Shishaldin is to aviation, but no flights had been impacted, and no ash fall was expected in communities last week.
The last significant eruptive activity was on Dec. 12, which only lasted a few minutes, but produced a similar ash cloud. Significant lava flow was seen in late December.
The AVO is monitoring the volcano closely. Haney said there are no indications of a major eruption, but that Shishaldin is a volcano with an ability to ramp up quickly.
"It's one of the most active volcanoes in the Aleutian Islands," said Haney. "Previous to this, it had an eruption in 2013. It also erupted in 2004. And it's last major eruption was in 1999, which produced an ash cloud to above 40,000 feet, perhaps as high as 50,000 feet."
Haney said the Jan. 3 event seems in line with the activity seen at Shishaldin over the past few months. No other signs of unrest were observed over the weekend.
Shishaldin has had at least 54 episodes of unrest, including over 24 confirmed eruptions since 1775.
The alert level remains at "watch."
