(CNN)A tsunami hit Tonga’s largest island, Tongatapu, reportedly sending waves flooding into the capital after an underwater volcano in the South Pacific exploded in a violent eruption, propelling a cloud of ash and gas steam into the air.
Waves crossed the shoreline of Nuku’alofa, Tonga’s capital, flowing onto coastal roads and flooding properties Saturday, according to CNN affiliate Radio New Zealand (RNZ), which reported residents headed for higher ground as waves swept the palace grounds, waterfront and main street.
Meanwhile, Tonga’s King Tupou VI was then evacuated from the Royal Palace, RNZ said, citing local media reports of a convoy of police and troops rushing the monarch to a villa at Mata Ki Eua.
The tsunami came after the eruption of the Hunga-Tonga-Hunga-Ha’apai volcano, about 30 kilometers (18.6 miles) southeast of Tonga’s Fonuafo’ou island, according to RNZ, and about 65 kilometers (40 miles) north of Nuku’alofa.
The volcano first erupted Friday, sending a plume of ash 20 kilometers, or 12.4 miles, into the air, per RNZ. A second eruption occurred Saturday at 5:26 p.m. local time, RNZ reported.
Satellite imagery showed a massive ash cloud and shockwaves spreading from the eruption. Ash was falling from the sky in Nuku’alofa Saturday evening and phone connections were down, RNZ said.
The eruption had effects across the Pacific, as tsunami warnings and advisories were issued from parts of New Zealand and Japan to the United States: A tsunami warning was issued for the islands of Tonga and parts of Japan, while tsunami advisories were issued for New Zealand’s North Island and the west coast of the US from California to Alaska, as well as Canada’s British Columbia.
Per the National Weather Service, a tsunami warning means those nearby should get inland or seek higher ground immediately, while an advisory means they should stay away from the shore and out of the water.
Tsunamis were reported along Japan’s coast early Sunday, according to Japanese public broadcaster NHK. The highest observed was 120 cm, or 3.9 feet, at Amami Oshima Island in Kagoshima Prefecture, followed by a 110 cm, or 3.6 foot wave at Kuku Port in Iwate Prefecture, NHK reported.
Japan’s coast guard was out assessing damage, but so far none had been reported, NHK reported, noting it was still dark and more waves were expected. Officials continued to ask people to stay alert and away from beaches.
Japan’s Meteorological Agency issued a tsunami warning for the southern Amami island and Tokara island chain in Kagoshima Prefecture and a tsunami advisory for all coastal areas facing the Pacific Ocean, NHK reported. The agency later issued another tsunami warning for the Iwate Prefecture in northern Japan.
Footage shared on NHK from a viewer in Setouchi Town on Amami Oshima Island showed bumper-to-bumper traffic as cars evacuated to higher ground. Other footage showed people sleeping on floors in evacuation centers in Iwate Prefecture, where a tsunami warning remained in effect.
Elsewhere, Australia’s Bureau of Meteorology said it recorded a tsunami wave of 1.2 meters (about 4 feet) near Nuku’alofa at 5:30 p.m. local time on Saturday. And the Pacific Tsunami Warning Center said tsunami waves of 2.7 feet (83 cm) were observed by gauges at Nuku’alofa and waves of 2 feet at Pago Pago, the capital of American Samoa, Reuters reported.
The nearby island of Fiji also issued a public advisory asking people living in low-lying coastal areas to “move to safety in anticipation of the strong currents and dangerous waves.”
A tsunami watch is in effect for all Samoan low-lying coastal areas, the Samoa Meteorological Service said, with residents and visitors advised to stay away from beach areas.
An earlier tsunami advisory for the Pacific island nation of Vanuatu was discontinued, with the nation’s National Disaster Management issuing an “all clear.” The office had earlier advised residents to move away from the coastline and seek higher ground.
Impacts already seen in the US
The eruption near Tonga also sent waves to the US West Coast, with some exceeding 3 and 4 feet in height, according to the National Weather Service office in San Diego.
The highest waves recorded were in Port San Luis, California (4.3 feet); King Cove, Alaska (3.3 feet); Area Cove, California (3.7 feet); Crescent City, California (3.7 feet); and Port Reyes, California (2.9 feet).
The first tsunami waves were felt on the US West Coast early Saturday morning, Dave Snider, the tsunami warning coordinator at the National Weather Service’s National Tsunami Warning Center in Palmer, Alaska, told CNN.
A wave as high as 1.2 feet had been observed in Nikolski, Alaska, he said via telephone, while waves as tall as one foot were observed in Atka, Adak and King Cove, Alaska.
“This may not be the largest wave as this is coming in yet,” Snider told CNN, saying the event was not over.
The waves reaching the US come after a tsunami advisory was issued for the US west coast, including the states of California, Oregon, Washington and Alaska, according to the National Tsunami Warning Center.
The Pacific Tsunami Warning tweeted no damage was reported thus far from the tsunami observed in the Hawaiian Islands. A tsunami advisory for Hawaii was canceled by the agency Saturday morning.
Adam Weintraub, a spokesperson for the Hawaii Emergency Management Agency, told CNN there were “no reports of major damage so far,” though the effects had been felt across multiple islands. Officials were still assessing the damage.
The impacts were the equivalent of a “high King Tide,” Weintraub said earlier, telling CNN there had been flooding in parking lots and harbor areas he characterized as “nuisance flooding.”
Speaking by telephone, Snider said, “We don’t have a really good forecast because this event is based on a volcano rather than an earthquake.” He noted the US west cost currently faces an advisory, and not a tsunami warning.
Nonetheless, the National Weather Service in Seattle urged caution along the US Pacific Coast on Saturday. “Move off the beach and out of harbors and marinas in these areas,” NWS Seattle tweeted.
“Strong currents and larger waves are possible along these coastal areas. The first wave may not be largest,” the agency went on to warn, adding larger waves may continue to hit the coast for hours after the initial wave.
“Continue to stay out of the water and away from shore along the coastal areas and continue to monitor for updates,” the agency said.
The city of Laguna Beach, California, closed all beaches, boardwalks, harbors and piers until further notice in response to the tsunami advisory early Saturday morning, telling residents, “please stay out of the water and away from the shore.”
Santa Cruz, California, also experienced some “minor flooding” at the harbor, city manager Elizabeth Smith told CNN.
The waves came right at high tide, Fire Chief Rob Young said. The initial wave occurred at approximately 7:40 a.m. local time, he said, bringing with it a one to two-foot wave right at the peak of high tide. The largest wave came in at about 8:49 a.m. local time, prompting a surge of about 7 feet at the harbor. A subsequent surge just after 10 a.m. was “diminished.”
“When it comes, it comes quickly,” he said. “Not just a one-foot wave, but it comes in a surge because it draws all the water out first, and then it comes in.”
There was some damage in the harbor and to some docks, he said. There was also “light flooding” on the beaches and up to the city’s first surface street, Young said.
All beaches and the harbor will be closed until at least noon local time, Smith said, and people were evacuated from nearby stores and the area near the harbor, though no one has been evacuated from their homes. A surf contest has been postponed and is expected to resume later Saturday.
New Zealand on alert
A tsunami advisory was also issued for coastal areas on the north and east coast of New Zealand’s North Island and the Chatham Islands, where “strong and unusual currents and unpredictable surges at the shore” were expected, according to New Zealand’s National Emergency Management Agency.
New Zealand’s official weather service said its weather stations across the country had observed “a pressure surge” on Saturday evening from the eruption.
Scientist Emily Lane, of New Zealand’s National Institute of Water and Atmospheric Research, told the New Zealand Science Media Centre it was a “very significant” eruption.
“The shock wave from it is clearly visible in satellite imagery and there are reports of the eruption being heard at least as far away as New Zealand,” she said. “The tsunami from the eruption has reached over 2,500 km being recorded on gauges over all of Aotearoa.”
Tsunamis generated by volcanoes are much less common than tsunamis from underwater earthquakes, Lane said.
A smaller eruption in late 2014/early 2015 built up the crater of the volcano to above the surface of the water, Lane added, but it’s not yet clear exactly how Hunga-Tonga-Hunga-Ha’apai erupted on this occasion. “When we see what is left of the island after this eruption is over we can start to put together the pieces of what happened,” she said.
Professor Shane Cronin, from the School of Environment at the University of Auckland, told the New Zealand Science Media Centre research into historical eruptions by the same volcano suggested the current eruption episode could last for weeks or months “and further similar-sized eruptions to the 15 January 2022 event are possible.”
“The eruption is likely to result in significant ash fall (cm to ten cm) in Tongatapu as well as the Ha’apai group of islands,” he said. “Help will be needed to restore drinking water supplies. People of Tonga must also remain vigilant for further eruptions and especially tsunami with short notice and should avoid low-lying areas.”
An earlier tsunami warning issued for American Samoa has since been canceled, according to the NWS Pacific Tsunami Warning Center.
There is no tsunami threat to Guam and the Commonwealth of the Northern Mariana Islands from a “distant eruption,” according to the Pacific Tsunami Warning Center.
The volcano had been active from December 20, but was declared dormant on January 11, according to RNZ.
CNN’s Dave Alsup, Jennifer Hauser and Haley Brink contributed to this report.