A volcano in Alaska that has been active for the past six months has erupted again, raising the aviation alert level to red. According to Bloomberg, the Alaska Volcano Observatory detected an eruption of the Bogoslof Volcano in the Aleutian Islands at approximately 2:16 p.m. on Sunday. The eruption lasted for 55 minutes and sent an ash plume at least 35,000 feet into the air.
In response to the eruption, the Aviation Color Code has been raised to red, the highest possible level. Airborne volcanic ash can interfere with and even destroy jet engines above 20,000 feet. Flights between North America and Asia are likely to be grounded, potentially for several days.
Bogoslof Volcano is a submarine stratovolcano, a conical volcano built up over many layers. Its absolute summit forms Bogoslof Island, located on the southern edge of the Bering Sea, 35 miles northwest of Unalaska Island, 850 miles southwest of Anchorage. Over the last six months, according to U.S. News & World Report, the island has more than tripled in size as a result of frequent eruptions. The last eruption occurred on May 17, sending ash clouds 34,000 feet high; Sunday's eruption marks the most significant to date. Starting in December, the volcano erupted almost daily. As of March 11, 2017, Bogoslof Island had grown to 242 acres in size and is expected to continue to grow.
The first known emergence of Bogoslof above sea level was in 1796, during an underwater eruption; another island about 2,000 feet northwest of Bogoslof, called Castle Rock, represents another cone of the same volcano which erupted later that year. Before December, 2016, Bogoslof's last known eruption was in 1992, and Bogoslof's current period of activity has come as a surprise to scientists.
Geophysicists, meanwhile, are excited, saying that the Bogoslof Volcano is providing new research opportunities.
"It's different from most of the other volcanoes we deal with," said Hans Schwaiger, a geophysicist with the Alaska Volcano Observatory. "It comes through the ocean, and so there's a different character to the plumes, there's more lightning detection we're getting off these so it's an interesting science study as well."
"If we think it may have another explosive event, if seismicity is still high we might keep it at Red for a while, but it had dropped down to lower levels and it was essentially at background levels, so we wanted to reduce it down to orange," he added of the May 17 eruption - today's was relatively unexpected.
Scientists still have a lot to learn about both the location and activity of underwater volcanoes; many modern techniques for identifying submarine volcano eruption rely entirely on sound.
According to the AVO, the ash cloud may reach as high as 45,000 feet, and while seismic and infrared detectors on neighboring islands, as well as satellite imagery, show all-quiet at Bogoslof, the volcano is "unpredictable" and AVO has issued a warning that "Bogoslof volcano remains at a heightened state of unrest and in an unpredictable condition. Additional explosions producing high-altitude volcanic clouds could occur at any time." They also warned that low-level explosions occurring below their detection threshold may be ongoing and that approaching the island is unwise.
The National Weather Service Alaska Aviation Weather Unit also issued an alert that the ash cloud may climb as high as 50,000 feet.
Local observers reported a "large white-gray mushroom cloud" over the volcano, which was causing continued ash fallout to the west of the eruption.
Update: The National Weather Service has also issued a warning for a trace dusting of ash over the coastal waters near the island.
[Featured Image by Dana Stephenson/Getty Images]