Tonga Underwater Volcano Erupts, Setting Off Tsunami Warnings Across Pacific

The volcano erupted near the remote island nation of Tonga, triggering a chain of warnings and causing strong waves as far away as the United States.

An underwater volcano erupted on Saturday near the remote Pacific nation of Tonga, triggering tsunami warnings across the Pacific and for the West Coast of the United States, and causing strong waves and currents in many coastal areas.

The volcano’s eruption was dramatic, sending plumes of gas and ash thousands of feet into the atmosphere, though early reports of damage were limited.

A four-foot tsunami wave was reported to have hit Tonga’s capital, Nuku’alofa, sending people rushing to higher ground, and witnesses said ash had fallen from the sky. There were no immediate official reports on the extent of injuries or damages, but internet service in the country was disrupted, according to The Associated Press, making it difficult to assess.

Despite Tonga’s geographical isolation, a booming sound after the initial eruption was heard as far away as New Zealand, 1,100 miles southwest of the archipelago’s main island of Tongatapu.

In the United States, officials urged residents of coastal areas in much of the West Coast, Alaska and Hawaii to stay away from the coastline and move to higher ground. The National Weather Service in Portland, Ore., reported possible one- to three-foot waves in some areas of Oregon and Washington. “First wave may not be the highest,” and later waves may “be larger,” the agency said on Twitter.

In California, water surged into Santa Cruz Harbor on Saturday morning, damaging boats, submerging the parking lot and causing people to evacuate the docks, sidewalks and nearby stores. At Port San Luis Harbor, about midway between San Jose and Los Angeles, waves of more than four feet were measured by the National Oceanic and Atmospheric Administration.

In the Bay Area, the National Weather Service said tsunami surges of up to a few feet could arrive in “pulses” throughout the day, and warned residents not to try to identify their arrival. “These water level surges can overwhelm and overtake people and pull them out to sea,” the agency said on Twitter.