A tsunami advisory is in effect for the West Coast of the United States after a volcano erupted in the Pacific. “A tsunami has been confirmed and some impacts are expected,” the National Weather Service’s National Tsunami Warning Center said early Saturday.

A tsunami advisory is in effect for the following areas, 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.

The advisory was issued after an undersea volcano erupted Saturday near the nation of Tonga in the Pacific. A tsunami warning was in effect for all of the archipelago, according to the Tonga Meteorological Services, and 2.6 foot-waves were detected, Pacific Tsunami Warning Center data showed, according to The Associated Press.   

In the U.S., the National Tsunami Warning Center said strong waves and currents are possible in areas under a tsunami advisory. “Some impacts may continue for many hours to days after arrival of the first wave,” the center said.

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 the 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.