The U.S. West Coast was bracing Saturday for tsunami activity — including unpredictable currents, waves and tides that could endanger swimmers and boaters — after an undersea volcano erupted near the Pacific nation of Tonga.
The eruption sent tsunami waves crashing ashore in the small island nation of about 105,000 people, sending people rushing to higher ground.
Meanwhile, a tsunami advisory is in effect for Hawaii, Alaska and the U.S. Pacific coast as officials urge people to avoid beaches and marinas Saturday.
Dave Snider, tsunami warning coordinator for the National Tsunami Warning Center in Palmer, Alaska, said the advisory includes an unusually long stretch of coast.
“I’m not sure when the last time was — but it really isn’t an everyday experience,” he said. “I hope that elevates the importance and severity for our citizens.”
Beaches and piers were closed in Southern California as a precaution due to possible strong rip currents. But the National Weather Service said there were “no significant concerns about inundation.”
West Coast officials warn residents to stay away from beaches
The National Weather Service offices in California said beaches may see impacts for several hours, starting Saturday morning.
The NWS warned people to avoid beaches, harbors and marinas and to not go to the shore to watch the tsunami.
“Please move off the beach and out of the harbors and marinas. Avoid the coastline. Do not go to the coast to watch the tsunami,” tweeted San Diego County. Oregon’s public safety office issued a similar warning.
Many California beaches and piers closed Saturday morning, including Berkeley Marina.
Seismologist Lucy Jones also warned people in affected areas to stay away from beaches, adding that moving water has “huge momentum” that can do damage in port areas. But she said if people are more than three feet above sea level, the waves likely will not affect them.
“Tsunamis are not one wave,” she said on Twitter. “It’s more like sloshing and that sloshing can continue for a day. Just because the first wave has passed, it is not time to go see the beach.”
Satellite images show eruption in Tonga
Social media videos from Tonga showed large waves crashing ashore and streaming around houses and buildings. The Tonga Meteorological Services said waves of 2.7 feet had been detected and issued a tsunami warning for all of the archipelago.
There were no immediate reports of injuries, though communications with Tonga remained cut off hours after the eruption. Police and military evacuated Tonga’s King Tupou VI from his palace near the shore, the Islands Business news site reported.
In the nearby island nations of Fiji and Samoa, authorities also issued warnings and told people to avoid the coastline due to strong currents and waves.
Satellite images showed the huge eruption as a 3 mile-wide plume of ash and gas rose like a mushroom to about 12 miles above the water. Scientists noticed large explosions, thunder and lightning near the volcano after it began erupting Friday.
Waves slam ashore in Hawaii
Waves from a foot to 2.7 feet slammed ashore in Hawaii, the Pacific Tsunami Warning Center reported. The center said there was no reported damage and only minor flooding.
The waves are just under the criteria of three feet for a more serious tsunami warning, Snider said. He said the area should expect waves and strong currents for many hours, and some marinas and harbors may see flooding.
“The important thing here is the first wave may not be the largest,” he said. “We could see this play out for several hours. It looks like everything will stay below the warning level but it’s difficult to predict.”
Contributing: The Associated Press