Bogoslof volcano in the Aleutian Islands was continuing to produce ash and aviation concerns after its third eruption of the week Friday morning.
The Alaska Volcano Observatory said in a Friday update that it had raised the aviation color code for the volcano, about 60 miles west of Unalaska, to red and its status to "warning" at about 11:15 a.m. in response to reports of a "short-lived explosive eruption."
"A Coast Guard ship in the vicinity reported ash emission as well as ejection of lava and fragmental material," AVO staff wrote. "According to the Coast Guard, ash emission subsided at about 10:37 (a.m. Alaska time)."
John Lyons, a geophysicist at the observatory, said a major storm in the area was interfering with volcanologists' attempts to get signals from monitoring stations on islands near Bogoslof Island, which was radically altered during eruptions this week.
Reports of the eruption Friday, which started at about 9:30 a.m., were being relayed through Coast Guard watchstanders.
"They reported activity for about an hour and seven minutes," Lyons said. "We don't have any visual observations yet because it's cloudy, and the plume didn't go above the regional cloud deck, which is 30,000 feet."
Lyons said forecasted winds in the area were expected to take any ash over water to the northeast, with no ashfall expected in any Alaska communities.
The National Weather Service's aviation desk in Anchorage has been tracking issues related to Bogoslof since Wednesday, when dozens of lightning strikes – which Lyons called "the defining characteristic of this eruption so far" – were recorded at or near the volcano.
Anchorage-based NWS meteorologist Michael Kutz said that a trio of low-pressure systems in the Aleutians were expected to form a single system headed north near Nunivak Island by Sunday afternoon. He said the stormy conditions have been a factor in keeping Bogoslof ash from falling on land.
"(There's) one system that's creeping up on Dutch Harbor and a second low out near Adak and a third near the end of the chain," Kutz said. "If things were further to the south, like they had been earlier this week, we'd start seeing (ash) dragging over into the Aleutian chain and then moving toward us."
The Anchorage office was forecasting volcanic ash clouds over the Bering Sea, in an area north of the Aleutians to the west of Nunivak Island, in an aircraft advisory set to expire around 10 p.m. Friday.
NWS aviation meteorologist Joshua Maloy said officials had some difficulties detecting the ash Friday evening due to clouds in the affected area. But the plume should dissipate and weaken overnight, he said.
Alaska Dispatch News reporter Jerzy Shedlock contributed to this report