Two volcanoes erupted Thursday on the far eastern Kamchatka Peninsula, tossing massive ash clouds kilometers into the air, forcing flights to divert and blanketing one town with thick, heavy ash.
The Klyuchevskaya Sopka, Eurasia's highest active volcano, exploded along with the Shiveluch volcano, 70 kilometers to the northeast, the Emergency Situations Ministry's branch in Kamchatka said, adding that flights in the area had to change course.
Ash clouds from the remote volcanoes billowed up to 10 kilometers and were spreading east across the Pacific Ocean, volcanologist Sergei Senyukov told Rossia One television. Streams of lava flowed down the slopes of Shiveluch.
The Volcanic Ash Advisory Center in Tokyo issued an advisory for planes to be alert for the ash cloud, although Tokyo's Narita Airport said it had no flights diverted yet.
Volcanic ash blanketed the nearby town of Ust-Kamchatsk, reducing visibility to only a few meters and turning buildings ghostly white. Emergency officials said the town's 5,000 residents were not in any immediate danger but urged them to stay indoors and tightly close doors and windows to avoid inhaling ash particles that could lead to respiratory illnesses and allergic reactions.
Schools and businesses in Ust-Kamchatsk quickly closed and all streets were shut down to traffic. Scientists warned that ashes would likely continue falling on the area for at least 10 days.
Ust-Kamchatsk is 70 kilometers east of Shiveluch and 120 kilometers northeast of Klyuchevskaya Sopka, and winds blew ash from both on the town.
Shiveluch quieted down later Thursday, but Klyuchevskaya Sopka, which stands 4,750 meters high, kept erupting, Russian officials said.
Jen Burke, a meteorologist with the Alaska Aviation Weather Unit, said ash from the Shiveluch eruption — the larger of the two — was moving across the Bering Sea at a height of 7,620 meters. That could put it in the path of planes flying between Asia and North America over Alaska.
"Right now it's not a difficult area to avoid because it's north of the Aleutian Islands," Burke said. "Planes could fly south of the Aleutian Islands and be perfectly safe."
She said ash might affect the extreme west coast of Alaska but winds were predicted to push the cloud north.
Kamchatka, which juts into the Pacific, is studded with active volcanoes.
The Emergency Situations Ministry warned Thursday that another volcano across the peninsula to the south, Gorely, has begun spewing gases and could erupt any moment. Gorely is located about 70 kilometers south of Kamchatka's regional capital, Petropavlovsk-Kamchatsky.