[UPDATE 6:12 p.m.: Tsunami Advisory Cancelled] West Coast Under Tsunami Advisory After Underwater Volcanic Eruption Near Tonga Islands

A tsunami advisory has been issued for America’s West Coast including California, Oregon, and Washington after an underwater volcano exploded near Tonga, an archipelago in the South Pacific Ocean. The eruption was reportedly violent sending ash skyward and causing flooding in Tonga’s capital, Nuku’alofa.

Mapping provided by the National Weather Service’s Tsunami Warning System indicates northern California’s coastal regions from Del Norte County to the Mexican Border are included in this advisory.

As per information issued by the National Weather Service, the tsunami is slated to arrive on the Mendocino County coast at approximately 7:35 a.m., in Crescent City around 8:00 a.m., and in San Francisco at 8:00 a.m.

This advisory means that “a tsunami capable of producing strong currents or waves dangerous to people in or very near the water is expected.”

It is important to note that as per the Tsunami Warning system, “Significant widespread inundation is not expected for areas under an advisory.”

For ocean goers, be aware that “currents may be hazardous to swimmers, boats, and coastal structures and may continue for several hours after the initial wave arrival.”

The forecasted wave heights of the tsunami are reported to be 1-3 feet and the National Weather Service described these sorts of events as “a series of waves of surges which could be dangerous for many hours after the first wave.”

An update regarding the advisory is being issued every half hour as officials monitor the evolution of the incident which can be accessed on their Facebook page or their website.

Please, North Coast residents, consider safety protocols issued by the National Weather Service to stay out of the water, away from beaches, and affected waterways.

UPDATE 7:01 a.m.: The National Tsunami Warning Center is reporting “boats are up on docks in Hawaii” but the coastline is not seeing inundation.

Along with this update was the warning that West Coast residents should be prepared for impacts in the bays and harbors.

UPDATE 7:16 a.m. More predictions continue to come in regarding the extent of the tsunami on the North Coast. A Facebook post from the US National Weather Service predicts the initial waves are expected to hit the coast between 7:30 a.m.-8:00 a.m. with “as much as 3 feet of tsunami wave” expected.

Low-lying areas places along the North Coast could possibly flood, such as King Salmon in the Humboldt Bay. The National Weather Service compared this to “some of the highest king tides we have seen earlier this month and in December.”

UPDATE 7:28 a.m.: The US National Weather Service in Eureka stated at 7:00 a.m. the main impacts of this series of waves will be “strong rip currents and coastal flooding of some immediate coastal low-lying areas.” They asked residents to “stay back from the beaches and lowest-lying areas.”

UPDATE 8:00 a.m.: An update from the National Weather Service in Eureka state that a “tsunami surge is occurring along the coast of Northern California and will continue to midday.” The post warned currents will be strong in bays and harbors and asked residents to “stay off docks, boats, and the shore.” Coastal flooding is also possible near high tide, between 9-9:30 a.m

UPDATE 8:23 a.m.: The National Weather Service in Eureka is predicting coastal flooding “will be possible for low lying areas near high tide around 9:15 a.m.”

The graph below depicts a water level anomaly due to the tsunami surge at 8:00 a.m. in Arena Cove along the Mendocino County coast.

UPDATE 8:32 a.m.: Video of the volcano explosion.

UPDATE 8:33 a.m.: An individual was photographed dangerously close to the water on Fort Bragg’s Noyo Harbor prompting a post on the US National Weather Service Eureka California Facebook page imploring the public to be cautious.

Photograph of people close to the waves as the tsunami hits the land.

They state, “We realize the desire to watch the water during tsunami activity…but PLEASE STAY WELL BACK from low-lying coastal areas, and especially the surf zone, through midday.” Initial tsunami waves began to arrive around 8:30 a.m., “but these may not be the largest, and tides will continue to rise through 9:30 AM,” the NWS warns.

UPDATE 8:48 a.m.: The Redwood Coast Tsunami Work Group on Facebook states the tsunami has so far been less than 18 inches thus far and is arriving “as the tide is high and the surf is large.” The post characterizes this morning’s event as a “relatively small tsunami” and expects only beaches and harbor areas to see impacts.

The group’s analysis provided reassuring news that “there is no need to evacuate homes and businesses in the mapped tsunami zone.”

This Facebook group is run by a number of North Coast scientists and geologists including Lori Dengler, a Humboldt State University professor renowned for her knowledge of earthquakes and tsunamis.

UPDATE 9:36 a.m.: This video was taken the morning of January 15, 2022, shortly before the tsunami caused by the Tonga Volcanic explosion came ashore on the Mendocino County coast. Typical of tsunami behavior, the water draws back before the swell of water washes ashore.

UPDATE 10 a.m.: According to the National Weather Service, high tide will make the situation more dangerous, they urge the community to “[a]void boating & fishing activity, as currents will remain strong for the next several hours. Avoid low-lying areas & stay off of rocks/jetties. Best to avoid these activities all day.”

With high tide coming soon, we urge people not to head to beaches or harbors. Avoid boating & fishing activity, as currents will remain strong for the next several hours. Avoid low-lying areas & stay off of rocks/jetties. Best to avoid these activities all day. North Spit gauge: pic.twitter.com/xgJU20wfTu

— NWS Eureka (@NWSEureka) January 15, 2022

UPDATE 11:33 a.m.: The National Weather Service is showing elevated water levels along the coast. See their tweet below:

Latest water levels from our three gauges along the NW CA coast. Stay back from beaches, harbors, rocks, jetties, and low-lying areas. It's best to go ahead and stay away or avoid these activities for the rest of the day.
Information can be found here: https://t.co/x44rhgCFYG pic.twitter.com/VlpdT4clF5

— NWS Eureka (@NWSEureka) January 15, 2022

UPDATE 1:25 p.m.: The National Weather Service reports that here are the latest observed heights over tidal predictions along the West Coast:

[Graphic from the National Weather Service in Eureka]

UPDATE 6:12 p.m.: Humboldt County Alert just sent out the following text, “The TSUNAMI ADVISORY for Humboldt County has been CANCELLED. Thank you for your enhanced caution and attention to safety recommendations during the event.”

UPDATE: North Coast Residents Document the Wild Waters of the Tsunami Sent from an Undersea Volcano Five-Thousand Miles Away