Sunday, July 21, 2024

[UPDATES] West Coast Under Tsunami Advisory After Underwater Volcanic Eruption Near Tonga Islands

The volcanic explosion as seen from a Japanese Meteorological Satellite

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.

[Map of the North Coast areas expected to experience the tsunami’s effects, from the National Weather Service]

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.”

May be an image of 3 people, people standing, outdoors and text that says 'TONGA GEOLOGICAL SERVICES TONGA GEOLOGICAL SERVICES TONGA GEOLOGICAL SERV CES'
Yesterday as geologists of the Tonga Geological Services watched as the volcanic eruption sent a plume of ash 12 miles into the air [From their Facebook page]

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.”

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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.

Tsunami Alerts--see text below
[Graphic from the National Weather Service]

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.

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No photo description available.

UPDATE 8:18 a.m.: For those interested in watching the waves associated with this moring’s tsunami surge, check out these live webcams from various locals on the Mendocino County Coast:

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.

No photo description available.

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.

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.

[Picture from the National Weather Service]

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.

May be an image of text that says 'NOAA/NOS/CO-OPS Tsunami Water Levels at 9416841, Arena Cove, CA From 01/14/2022 19:21 to 01/15/2022 19:21 GMT MLLW 2.0 ? meters in 1.0 Height 0.0 20:00 1/14 00:00 1/15 NOAA/NOS/Centenfor Operational Oceanographic Products Services 04:00 08:00 1/15 1/15 Date/Time (GMT) One Minute 12:00 1/15 Six Minute 16:00 1/15 Predictions Residual'
Data from Mendocino County’s Point Arena

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

May be an image of text that says 'NOAA/NOS/CO-OPS Tsunami Water Levels at 9419750, Crescent City, CA From 01/14/2022 19:21 to 01/15/2022 19:21 GMT 2.0 0 1.0 in Height 0.0 20:00 1/14 00:00 1/15 NOAA/NOS/Centenfo Operational Oceanographic Products and Services 04:00 08:00 1/15 1/15 Date/ Date/Time (GMT) One Minute 12:00 1/15 Six Minute 16:00 1/15 Predictions Residual'
Data from Del Norte County’s Crescent City

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 9:29 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 10:00 a.m.: MendoFever’s Coastal correspondent Judy Valadao cautiously made it to a safe purchase on the bluffs above Noyo Harbor took some photographs of the waves associated with the ongoing tidal surge.

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


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Matt LaFever
Matt LaFeverhttps://mendofever.com/
I have been an Emerald Triangle resident since 2006 and this is year ten in Mendocino County. Please, email me at matthewplafever@gmail.com if you know a story that needs to be told.

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