Waves were no higher than one-to-two feet after a tsunami warning on Saturday following a volcanic eruption in the South Pacific. Video screenshot from Fernando Haro.

A tsunami advisory remains in effect Saturday after an underwater volcanic eruption near the South Pacific island nation of Tonga, which sent waves flooding into the capital there.

A tsunami warning was issued for the entire US west coast, including California, Oregon, Washington and Alaska, according to the NWS National Tsunami Warning Center.

Waves were currently no higher than one-to-two feet, but even a small change in the current could have big impacts to vulnerable places like Long Beach, authorities said.

“It doesn’t take a lot” to snap the lines off boats and thrust the docks around, Long Beach Marine Safety Division Chief Gonzalo Medina said Saturday.

In Alamitos Bay, the Marine Safety Division has noticed there is currently a one foot decrease of water where the tide should be.

“At some point that water will come back,” Medina said. “And when it comes back with momentum and kinetic energy, that’s when we watch for the effects of the tsunami.”

The effects could end up costing Long Beach hundreds, if not thousands of dollars in damages to boats and docks, he said.

Seismologist Lucy Jones, founder of the Dr. Lucy Jones Center for Science and Society, said the expected short-term increase of 1-3 feet in sea level would only be an issue near the beach.

“Tsunamis are not one wave. 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,” Jones tweeted, adding that “much tsunami damage happens in ports because of the currents. Moving water has huge momentum.”

In preparation of the tsunami, the Marine Safety Division dispatched their rescue boats to advise others out at sea that they are safer outside of the harbor. According to Medina, the best place to be during a tsunami is deep inland or out in the open sea as the effects will be lessened in those areas.

“Most effects will be in the marina,” Medina said. “When it’s a volcano rather than an earthquake, some of the impacts and how the tsunami behaves are different and harder to predict.”

The department also sent lifeguard units out to the beach to give the public updates on the tsunami.

The waves were also relatively small at Seal Beach, where about 100 people gathered along the coast, though authorities closed the beach until further notice.

Jerry Day, 64, of Long Beach, said that as soon as he heard of the tsunami advisory, he woke his wife up because it was the first time in his 25 years living in Southern California that he heard of a tsunami advisory happening nearby.

“You know when the weatherman tells you not to go, you have to go?” Day said.

He went to Signal Hill’s hilltop first to see how tall the waves were going to get. When he saw that the waves were not coming in very high, he decided to go to the pier to get a closer look.

The estimated arrival time in the Long Beach-Los Angeles Harbor area was about 7:50 a.m., but Medina said the effects of the tsunami could be prolonged over a period of time.

Strong warnings were posted from the National Weather Service Los Angeles office. “This tsunami will bring large and dangerous rip currents to all Southern California beaches today,” NWS Los Angeles tweeted.

The Tsunami Warning Center’s Snider noted to CNN this is currently an advisory and not a stronger tsunami warning following the Tonga eruption.

City News Service contributed to this report.