An undersea volcano erupted near Tonga, causing a tsunami advisory for the U.S. West Coast

The eruption of an undersea volcano near Tonga caused massive waves along the coasts of the Pacific island nation and resulted in tsunami advisories for the West Coast of the United States, The Associated Press reported on Saturday.

A plume of ash and gas from the eruption rose nearly 12 miles above the Pacific Ocean, according to AP. It also caused a sonic boom that could be heard in Alaska.

What’s happening in Tonga?

According to AP:

• After the eruption, tsunami waves up to 2.7 feet tall crashed on the shores of Tonga, causing many people on the coast to run to higher ground for safety.
• Tonga’s King Tupou VI was evacuated from his palace, which is near the shore, and taken to higher ground by police and military troops.
• Internet service in Tonga was interrupted by the eruption, meaning that many government websites and sources have been unable to provide official updates on the situation. Family members and friends have also had difficulty communicating with each other about their safety.
• The military of New Zealand has said that it is ready to offer assistance in Tonga, if needed.
• Fiji and Samoa have also issued warnings to stay away from coastal areas, in case of strong waves.

What is the tsunami advisory for the U.S. West Coast?

• The National Tsunami Warning Center issued a tsunami advisory for the West Coast of the United States on Saturday morning, the New York Times reported.
• Residents of Hawaii, Alaska, California, Oregon and Washington were warned to stay away from the coastline and get to higher ground, according to AP.
• Rising water levels caused flooding in some parts of California, with waves over four feet tall being measured at Port San Luis Harbor, which is between San Jose and Los Angeles, per the Times.
• AP reported that the waves in Hawaii nearly reached the criteria for a more serious tsunami warning. The advisory in Hawaii has already been lifted.

What do we know about the volcano?

• The undersea volcano that erupted Saturday is called the Hunga Tonga Hunga Ha’apai volcano, and it is about 40 miles from Tonga’s capitol, Nuku’alofa, in the Pacific Ocean, according to AP.
• There had been some activity from the volcano in December, but it had stopped by Jan. 3 of this year, CNN reported.
• Underwater volcanoes are similar to volcanoes that are on land; however, underwater volcanoes can become bigger as they erupt, and the water can cause the lava to become more explosive, per AP.