Tsunami advisory in effect for U.S. West Coast after volcanic eruption: “Move

A tsunami advisory is in effect for the West Coast of the United States and Alaska after a volcano erupted in the Pacific. “A Tsunami is occurring,” the National Weather Service’s National Tsunami Warning Center said on Saturday.

“Move away from the shore and head to high ground,” it said, warning that the first wave may not be the largest.

A tsunami advisory — meaning “a dangerous wave is on the way” — was issued for the following areas, stretching from southern California to Alaska’s coastline, according to the warning center:

• The California coast from the California-Mexico border to the Oregon-California border, including San Francisco Bay.
• The Oregon coast from the Oregon-California border to the Oregon-Washington border, including the Columbia River estuary coast.
• The outer coast of Washington state from the Oregon-Washington border to Slip Point, Columbia River estuary coast, and the Juan de Fuca Strait coast.
• The north coast of British Columbia, and Haida Gwaii, the central coast and northeast Vancouver Island, the outer west coast of Vancouver Island, the Juan de Fuca Strait coast.
• The inner and outer coast of Southeast Alaska from the BC-Alaska border to Cape Fairweather, Alaska.
• South Alaska and the Alaska Peninsula: Pacific coasts from Cape Fairweather, Alaska, to Unimak Pass, Alaska.
• Aleutian Islands: Unimak Pass, Alaska, to Attu, Alaska including the Pribilof Islands.

An advisory was also issued for Hawaii. It was later canceled, after wave heights there started to diminish. 

“Small sea level changes, strong or unusual currents may persist for several additional hours in some coastal areas and appropriate coastal areas and appropriate caution should be exercised by boaters and swimmers,” the Pacific Tsunami Warning Center tweeted.

The advisories were issued after an undersea volcano erupted Saturday near the nation of Tonga in the Pacific. The damage there was unclear, as all internet connectivity with Tonga was lost on Saturday evening, according to Doug Madory, director of internet analysis for the network intelligence firm Kentik, The Associated Press reported.

A tsunami warning was in effect for all of the archipelago, according to the Tonga Meteorological Services, and 2.7 foot-waves were detected, Pacific Tsunami Warning Center data showed, according to the AP.

In California, the Governor’s Office of Emergency Services said tsunami heights were expected to be 1-2 feet, based on what was seen in Hawaii. Flooding was later reported near the Santa Cruz Harbor, and some residents were evacuated. Officials also said over 100 people evacuated the Berkeley Marina, CBS SF Bay Area reports.   

Washington was seeing tsunami waves that were less than one foot, but forecasters warned that later waves could be larger. 

“A Tsunami Advisory remains in effect for the Washington Coast and Strait of Juan de Fuca where 1-3 ft waves are likely,” the National Weather Service in Seattle tweeted. “That said, strong waves and currents cannot be ruled out for any part of the shorelines of WA, including the Puget Sound & Salish Sea.”

Live-aboards along the U.S. coast were urged to seek shelter.  

A tsunami advisory is one level below a warning — and one step above a watch. It means dangerous waves of 1-3 feet and strong currents are expected. 

“Remember that a tsunami isn’t likely to look like a classic ‘breaking wave;’ it’s more of a massive surge of water that can rise quickly and with great power,” said the Hawaii Emergency Management Agency.  

The tsunami warning center said some impacts “may continue for many hours to days after arrival of the first wave.” Later waves may be larger than any initial wave, and “each wave may last 5 to 45 minutes as a wave encroaches and recedes,” according to warning center.  

Signs of a tsunami include strong currents, a shoreline that has receded or is receding quickly, and unusual waves and sounds. “The tsunami may appear as water moving rapidly out to sea, a gentle rising tide like flood with no breaking wave, as a series of breaking waves, or a frothy wall of water,” the National Tsunami Warning Center said. 

Dave Snider, tsunami warning coordinator for the tsunami warning center in Palmer, Alaska, said it isn’t an “everyday experience” for an advisory to be issued for this length of coastline. “I’m not sure when the last time was,” he said.

“I hope that…