A code red aviation warning was issued by the Alaska Volcano Observatory (AVO) Monday, meaning an “eruption is imminent with significant emission of volcanic ash into the atmosphere likely.”
The warning cites “seismic and infrasound activity” since the volcano’s explosive three-hour eruption on Monday afternoon.
Monday’s event was “longer-lived” than most of Bogoslof’s many previous eruptions, according to Hans Schwaiger, a geophysicist at the observatory.
After a quarter-century break, the small volcano erupted back to life in December 2016, and has exploded about 60 times since.
Prior to Monday, the volcano had been quiet for about two weeks, however it is known to erupt “once or twice a week, on average,” with usually “very little to no warning.”