The Future Is Here
We may earn a commission from links on this page

The West Coast Is Under a Tsunami Warning After Violent Tonga Volcanic Eruption

Nations across the Pacific have sounded the alarm about tsunamis after a violent eruption shook one of Tonga's volcanoes.

We may earn a commission from links on this page.
Satellite imagery of Tonga’s massive volcanic eruption on Saturday.

A major volcanic eruption has rocked the small island nation of Tonga, causing tsunami warnings to go up across the Pacific from Australia to the U.S.

Spectacular and terrifying satellite imagery shows Hunga Tonga-Hunga Haʻapai volcano exploding on Saturday. A massive cloud of ash appeared over the Pacific, unleashing havoc in Tonga. The BBC reported blackouts across the island nation as well as cell phone and internet outages. The outlet also noted that people reportedly heard the boom as far away as New Zealand, roughly 1,300 miles (2,500 kilometers) away, as well as Fiji and Vanuatu.


Shortly after the eruption, a tsunami hit the capital of Nuku’alofa. The wave reached a height of roughly 4 feet (1.2 meters). Despite the tense scenes, there have been no reports of casualties so far. The sun is set to rise shortly in Tonga, which will give officials a better chance to assess the damage, get the lights back on, and help residents in need.


Tsunami Warnings Ring the Pacific

The danger of tsunamis, however, extends well beyond Tonga’s shores. Australia and New Zealand have issued tsunami warnings and told residents to avoid coastal areas. Australia also issued an evacuation order for Lord Howe Island, a small part of New South Wales that sits around 350 miles (575 kilometers) off the coast. In addition to the tsunami warning for New South Wales, the entire east coast of Australia remains under a “marine threat” due to dangerous rip currents, strong waves, and the possibility of localized flooding as water sloshes ashore.

The West Coast and Hawaii Have Already Seen Tsunamis

Waves have already arrived in some cases. The National Weather Service Tsunami Alert tweeted that boats were washed onto docks and out of the water in parts of Hawaii in the early hours of Saturday local time. Kauai reported wave heights of 2.7 feet (0.8 meters), and more pulses could come through in the next few hours.


The peak tsunami height observed in the U.S. so far is 4 feet, with the reading coming from Port San Luis, California, a bayside community south of San Luis Obispo. But there’s still more surging water to come. “The tsunami waves will arrive in pulses throughout the day,” the NWS San Diego office warned.

Even parts of Alaska saw tsunami waves higher than 1 foot (0.3 meters) in height hit in the early hours of Saturday as well. While these heights may not sound impressive, they still pose a major danger. The force and speed of tsunami waves can easily overtake those who get too close and do serious damage as they enter constricted waterways like bays, harbors, and the mouths of rivers. In short, heed the warnings if you’re anywhere in the tsunami alert zone.


“We don’t issue an advisory for this length of coastline as we’ve done—I’m not sure when the last time was—but it really isn’t an everyday experience,” Dave Snider, tsunami warning coordinator for the National Tsunami Warning Center, told the AP. “I hope that elevates the importance and severity for our citizens.”


This Is the Latest Eruption in Tonga’s Volcanic Legacy

Tonga sits along the Ring of Fire in the Pacific, home to a number of the world’s most active volcanoes. Hunga Tonga-Hunga Haʻapai is actually a relatively new volcano, at least as far as its above-water parts are concerned. It emerged from the Pacific in 2009 in the breach between two islands that are themselves part of the volcanic caldera. The volcano has expanded since 2015.


The volcano was rumbling in the month before this weekend’s major eruption. During the week spanning 2021 and 2022, the Smithsonian Volcanic Institute reported steam plumes and gases rising as high as 39,400 feet (12,000 meters) over the volcano. Those plumes were even visible on satellite imagery as the calendar turned over, apparently a precursor to Saturday’s main event.

The eruption wasn’t just an ash producer. The explosion also set off a surreal lightning storm, with data collected by meteorology firm Vaisala showing a staggering 400,000 bolts of lightning in the wake of hours following the eruption.


This is a developing story and will be updated.