Update 6:45 a.m. Wednesday:
An explosion at Bogoslof volcano was recorded at 9:18 p.m. Tuesday by the Alaska Volcano Observatory, which issued an update raising the volcano's aviation color code to red and its alert level to "warning."
"This event was short-lived, lasting only a few minutes, but was detected in seismic, infrasound and lightning data, and formed a volcanic cloud that was visible in satellite images," AVO staff wrote.
The blast may have sent ash as high as 33,000 feet, the observatory said, but prevailing winds were carrying the cloud north over the Bering Sea.
The restless Bogoslof volcano began 2017 with another small eruption, continuing weeks of seismic activity on the remote Aleutian island.
On Monday, seismic sensors on nearby islands picked up a "volcanic signal" from Bogoslof starting at 1:53 p.m. that suggested an "ash-producing eruption had occurred," the Alaska Volcano Observatory said in an online update.
"The short duration of seismicity and lack of evidence for ash above the clouds in satellite data suggest this was a relatively minor explosion," the update said.
An aviation alert from AVO remained at level "orange" following the explosion.
The volcano is on a tiny, young island about 60 nautical miles northwest of Dutch Harbor that is home to seabird, fur seal and sea lion rookeries. The island is part of the emerging summit of an underwater volcano.
The volcano had previously erupted on Dec. 30.