Tsunami hits Tonga and heads for US west coast

An underwater volcanic eruption in the Pacific has triggered Tsunami warnings. The hardest hit is the island of Tonga and NPR reported that communications with the island had been cut off.

The first major volcanic eruption struck today in the island nation of Tonga. Over the past few weeks, the small volcanic island of Hunga Tonga-Hunga Ha’apai had been experiencing minor but impressive explosions. However, on January 14-15, the eruption became much more violent, sending ash over 60,000 feet (18 kilometers) into the skies. The blast also generated a tsunami that hit many of the islands in Tonga, destroying homes and buildings across the country.

The blast was caught in spectular fashion by Japan’s Himawari-8 satellite. In this animated GIF (above), you can see the large explosion begin and the shockwave from the blast pass through the atmosphere away from the volcano for hundreds of miles like ripples in a lake. The shockwave was recorded in air pressure as far away as Anchorage having travelled over 5,800 miles (9,200 kilometers) and Florida. You can also see the thin, fast moving surge at the front of the growing cloud. This appears to be possibly the largest eruption in historic record for the volcano.

GOES-17, a NOAA weather satellite, caught the eruption plume forming as well (below). You can clearly see the initial upward thrust followed by the spreading of the cloud laterally as it hit neutral buoyancy in the atmosphere. The eruption also generated a large amount of volcanic lightning.

You can see the explosion in this news clip.

Tsunami warnings were triggered all along the west of the US. The waves hitting Tonga were in the 4 ft range but those reaching the US were in the 1-2 foot range, which does not sound like much, but can be dangerous to people on the shore, mainly because it can knock people over and when tsunami waves recede they can drag people back with it into the ocean.


  1. Trickster Goddess says

    Woke up this morning to a tsunami alert on my phone. I live a couple of blocks from the ocean. The alert was cancelled a couple of hours ago.

  2. Mobius says

    Am I the only one that noticed that the graphic and the weather lady on CNN gave the date as “Dec. 14”? I kept expecting someone to say “Sorry, that is Jan. 14.”

  3. prl says

    According to the USGS, not the ash:

    During major explosive eruptions huge amounts of volcanic gas, aerosol droplets, and ash are injected into the stratosphere. Injected ash falls rapidly from the stratosphere — most of it is removed within several days to weeks — and has little impact on climate change.

    But other components of the plume can make contributions:

    But volcanic gases like sulfur dioxide can cause global cooling, while volcanic carbon dioxide, a greenhouse gas, has the potential to promote global warming.


  4. says

    The way they talk on Chicken Noodle News, you’d think Canada doesn’t exist. Or their attitide is “who cares about their people?”

    Vancouver Island and the twistiness of the Juan de Fuca Strait will protect the False Creek inlet and Vancouver. But see those triangular shaped islands up the British Columbia coast? Next to them on the mainland is the town of Prince Rupert, a major North American port (about 1/3 the volume of Vancouver). Freight rail across Canada splits, and a lot goes through Edmonton and Prince Rupert instead of Calgary and Vancouver. After the flooding that wiped out parts of southwest BC, the port’s volume of traffic might have increased.


    Despite how tall the mountains are along BC, the area around Prince Rupert is very low in elevation. If it gets hit hard, expect to hear about more “supply chain” disruptions.

  5. Lassi Hippeläinen says

    Seems unlikely that a one metre tsunami in Southern Pacific could still be one metre when it reaches California. In oceans waves of that size are just background noise. Or they may be caused by ships passing by.

    Anyway, in this case big tsunamis seem very unlikely. The volcano is in shallow water, and the sea bottom is relatively flat. Not much chance for a big underwater landslide.

    BTW, there is no island called Tonga. It is an island group with more than a hundred islands. Most belong to three subgroups (Vava’u, Ha’apai, and Tongatapu), and then there are some outliers, like Niuafo’ou (known by stamp collectors as the Tin Can Island).

  6. birgerjohansson says

    It hit California at high tide, no injuries but some material damage from flooding. Not much by tsunami standards but a reminder of the need for vigilance.

  7. jrkrideau says

    @ 1 prl
    I think it’s more “tsunami heads all over the Pacific” than “heads for US west coast”:

    Heavy fog in English Channel, continent cut off.

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