Tsunami waves up to a foot high have reached the U.S. island territory of Guam, authorities said.

Similar wave heights will continue, but they are expected to gradually diminish in the coming hours, the Guam Office of Civil Defense said in a statement.

Possible effects include changes in sea level, minor flooding in coastal areas, and strong, unusual currents near the shore, it added.

China lifted yellow tsunami alerts for Shanghai and Zhejiang, according to the latest assessment by China’s Tsunami Warning Center under the Ministry of Natural Resources.

The alerts warned that tsunami waves from the earthquake off the coast of Russia could reach Shanghai by evening local time. The city relocated more than 280,000 people and suspended multiple flights, sea, and rail transportation services this morning as it prepared for the potential tsunami as well as the arrival of Typhoon Co-may.

Tsunamis are extremely rare in China. According to historical records cited by the Chinese Academy of Sciences, only 10 tsunamis have occurred in the past 2,000 years.

The first waves hit the Washington state communities of La Push and Westport in the past hour, the National Weather Service Seattle said in a post on X, citing tide gauges.

The weather service did not say how high the waves were, but forecasters have said the waves were expected to be under one foot for much of the West Coast.

The Pacific Tsunami Warning Center has downgraded its threat warnings for Hawaii to an advisory.

“Based on all available data a major tsunami is not expected to strike the state of Hawaii,” it said in a bulletin. “Strong currents may occur along all coasts that could be a hazard.”

Those who have evacuated may safely return home based on county assessments and directives, officials said.

In a separate bulletin, the center also canceled its tsunami advisory for Guam and the Northern Mariana Islands.

All workers were evacuated from Japan’s Fukushima nuclear power plants after an 8.8-magnitude earthquake off Russia raised tsunami fears.

No injuries have been reported so far, the Tokyo Electric Power Company said in a post on X, with the discharge of radioactive wastewater from the Fukushima Daiichi plant suspended to “ensure absolute safety.”

There are no abnormalities in facilities at either the Fukushima Daiichi or Fukushima Daini plants, it said. “We will continue to closely monitor tsunami information and any impacts to the plants.”

In 2011, a powerful earthquake and tsunami crippled the Fukushima Daiichi plant.

Waves have reached the California coast, the National Weather Service said in a post on X, adding that they were showing up in Arena Cove and making their way down the coast.

“First Tsunami waves are beginning to impact the coast with clear waves being recorded at the Crescent City and Humboldt Bay tide gauges,” NWS Eureka said separately.

“Waves will continue to build in through the night and will become more dangerous as we approach high tide,” it added.

Hawaiian Airlines says it is resuming flight operations as airports reopen.

Hawaiian and its sister airline, Alaska, had earlier put flights on hold as Hawaii braced for possible tsunami waves.  

Alaska Airlines operations will resume in the morning, Hawaiian Airlines said. Guests traveling to, from or within the Hawaiian Islands should continue to check the status of their flight, the airline said.

Hawaii Gov. Josh Green said earlier that all flights in and out of Maui had been canceled for the night.

More than 1.9 million people in Japan are under evacuation alerts.

The evacuation advisories cover 207 cities and towns across 21 prefectures, according to the nation’s Fire and Disaster Management Agency.

Waves of nearly 6 feet were recorded in Maui, according to NOAA data.

The Hawaii County Civil Defense Agency warned that follow-up waves over the next several hours could be larger. “These massive waves can wrap around the island shore, so impacts may occur at any point along the coast,” it said on X.

“It’s not over yet,” it added.

While Hawaii airports have not been affected by waves, all flights in and out of Maui have been canceled for the night, Gov. Josh Green said, adding that about 200 people were sheltering in the terminal.

He said that there had been no power disruptions in the state and that there were no plans to shut off power pre-emptively.

Hawaii has so far “not seen a wave of consequence, which is a great relief to us,” Gov. Josh Green told reporters. “It’s kind of a blessing to not be reporting any damage.”

But he cautioned that “we have seen significant water recede several times in Haleiwa, and there were two waves that were measured coming through the Midway Atoll, so that’s been our concern.”

“Until we see what happens on the Big Island and the full wraparound of the islands, we won’t feel that we are in a position to start seeing and saying that we’re kind of in the clear,” Green said, adding that it would be at least two to three hours before that.

“So far, though, at the moment, so good,” he said.

Tsunami waves are now affecting Hawaii, Honolulu’s emergency department said in an alert.

“Destructive tsunamis expected,” it said, urging people in warning zones to evacuate.

Ocean pulses from the Kamchatka Peninsula earthquake have already come ashore in Japan, but their size might seem puzzling.

The largest waves so far were measured at almost 24 inches, small waves compared with ocean surf. They arrived on the Japanese islands of Hokkaido and Honshu shortly after 1 p.m. local time, the country’s meteorological agency said.

The two Japanese islands were earlier hit by even smaller waves of about 12, 16 and 20 inches. No deaths or major damage have been reported so far.

Height may be deceiving: Tsunamis can be relatively low if they’re measured vertically, but they’re more often powered by their long length, which brings with it more potency than that of an everyday ocean wave.

An academic analysis of tsunami science on the National Oceanic and Atmospheric Administration website says there is no agreed-upon measure of potency for the waves, but it asserts: “Tsunamis are long waves of small steepness.”

The massive earthquake that struck off Russia could be one of the biggest ever recorded if its 8.8 magnitude remains unchanged.

According to the U.S. Geological Survey, the tremor off Russia’s Kamchatka Peninsula is tied for the sixth-largest on record, along with a 2010 earthquake off Chile. The agency said that the earthquake was shallow at a depth of about 13 miles and that it was centered about 75 miles east-southeast of the Russian city of Petropavlovsk-Kamchatsky.

It is the world’s largest earthquake since the 2011 earthquake off Japan, which had a magnitude of 9.1 and set off the Fukushima tsunami and nuclear meltdown. In Russia, it was the largest earthquake since one in the same area in 1952 that measured 9.0.

The biggest earthquake on record is the 1960 Valdivia earthquake in Chile, which had a magnitude of 9.5.

Hawaiian Airlines and Alaska Airlines said flights to Hawaii were on hold as the merged sister carriers monitor the expected tsunami and its aftermath.

“We are holding flight departures to the Islands on Hawaiian Airlines and Alaska Airlines,” Hawaiian said in a statement. Flights in the air were ordered to return to the mainland or divert to a suitable airport, it said.

Ticket-holders were asked to check the statuses of their flights before they head to their departure airports. Travel plans affected by the flight pause could be eligible for waivers, Hawaiian said.

More information can be found here.

The effects of the tsunami waves are initially expected to appear on the coast of Kauai, followed by the Big Island about 20 to 30 minutes later, the Hawaii County Civil Defense Agency said.

“These massive waves can wrap around the island shore, so impacts may occur at any point along the coast. AVOID THE AREA,” the agency said on X.

Witness videos captured the powerful 8.8-magnitude earthquake that struck Russia’s Kamchatka Peninsula in the far east. The earthquake triggered a tsunami alert, with the first wave hitting the coastal area of Severo-Kurilsk.

Japan’s meteorological agency said tsunami warnings remained in place since waves were still being observed and asked those in the warning zones to remain in safe locations.

Agency official Masashi Kiyomoto said each wave cycle was lasting about an hour and that there had been two to three cycles so far. He said it was too early to say whether the waves were getting larger with each cycle.

Based on similar-sized earthquakes in the region in the past, the tsunamis could last for about a day, he said.

Hawaii’s tourism chief tonight said visitors in high-rise hotels and resorts should head to higher floors where possible.

James Kunane Tokioka, state director of the Department of Business, Economic Development and Tourism, called such a move “vertical evacuation.”

“Properties along the coastline are being asked to evacuate vertically, four floors and above,” he said, meaning tourists should be at least on the fourth floor before any waves arrive.

The Waikiki coast in Honolulu is packed with high-rise hotels and resorts.

Japan, where the earthquake was barely felt, has reported the biggest tsunami waves so far, measuring 60 centimeters, or almost 2 feet.

One arrived at 1:11 p.m. local time (12:11 a.m. ET) in the town of Hamanaka in the southern region of the northernmost island of Hokkaido, according to Japan’s meteorological agency. The other was at 1:03 p.m. at Kuji port in Iwate Prefecture on Japan’s main island of Honshu.

Earlier, Japan reported waves on Honshu and Hokkaido of about 12 to 20 inches. Officials had said waves could reach as high as about 3 feet.

The Coast Guard has ordered all commercial vessels at commercial ports in Hawaii to evacuate.

In a post on X, the agency attributed the order to the captain of the Port of Honolulu. It also said all harbors in the state have been closed to incoming traffic.

In its advice about responding to a tsunami, the federal website ready.gov says, “If you are in a boat, go out to sea.”

The governor of Hawaii tonight emphasized that tsunami effects could be real and costly, as potent ocean pulses from the 8.8-magnitude quake east of Russia’s Kamchatka Peninsula were expected at around 7:17 p.m. local time (1:17 a.m. ET).

Gov. Josh Green said impacts are almost certain. “We do expect damage. We expect significant damage along the coastlines,” he said.

“We pray that we won’t lose any of our loved ones,” he continued.