Tsunami impacts hit West Coast after volcano eruption in Pacific; stay away from beaches, officials warn

West Coast authorities pleaded with residents to stay out of the Pacific Ocean and away from beaches on Saturday as the impacts of a tsunami caused by a volcanic eruption in the South Pacific began hitting the coast.

While forecasted waves were generally less than 3 feet, tsunami impacts create unpredictable currents and tides that could endanger swimmers and boaters. The waves are expected to arrive in pulses throughout the day.

"There are extremely powerful currents associated with the surges and if you are pulled into the water it will overpower you," the Marin County, Calif. Sheriff tweeted, sharing a photo of a damaged dock in the area.

Two people were taken to the hospital after being swept out to sea while they were fishing at San Gregorio State Beach in San Mateo County, Cal Fire said. The National Weather Service said there were reports of boats getting pushed up in docks, and isolated flooding was reported, including in beach parking lots at Port San Luis.

"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.

Despite warnings, surfers still made their way to Manhattan Beach and crowds gathered at the Santa Cruz harbor early Saturday to watch waves strain boat ties on docks.

A tsunami advisory is in effect for Hawaii, Alaska and the U.S. Pacific coast. 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."

Some 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 first waves arrived before 9 a.m. on the southern Oregon coast at over one foot tall, the NWS Portland said, reminding people that the highest waves will likely come later. California's central coast saw waves of up to 2.5 feet.

The largest waves have been observed in Port San Luis, Arena Cove and Crescent City, as of late Saturday afternoon, the NWS said. Port San Luis has seen waves as high as 4.3 feet while Arena Cove and Crescent City have seen 3.7-foot waves.

Responding to Twitter users sharing plans to swim during the tsunami advisory, the San Francisco Fire Department urged residents to not put themselves or rescue teams at risk.

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

The eruption occurred roughly 5,000 miles away from most locations on the West Coast, near the Pacific nation of Tonga. There, tsunami waves sent people rushing to higher ground and impacts from the eruption continue to disrupt communication with the nation.

Social media videos from Tonga showed large waves crashing ashore and streaming around houses and buildings.

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

Contact News Now Reporter Christine Fernando at cfernando@usatoday.com or follow her on Twitter at @christinetfern.