The January 14 volcanic eruption in Tonga not only triggered tsunami surges in coastal communities as far away as Japan and Canada, these same surges battered hundreds of boats throughout the region.
The most damage was done on Tonga’s largest island, Tongatapu, where volcanic ash covered the island and tsunamis brought down buildings along the coast. At press time, the Tongan government confirmed three deaths, although communications in and out of Tonga remained difficult, as power cuts had disrupted the cable system used to connect Tonga to Fiji and other international networks.
In addition to washing boats ashore in Tonga, surges impacted boats and marinas in countries to the southwest, in particular. In New Zealand, for example, the Tutukaka Marina suffered considerable damage as the boats there weathered a cyclone at the same time the tsunami waves were hitting.
“The combination of the storm surge from the cyclone plus those waves from the tsunami caused a lot of damage,” said Viki Moore, owner of Island Cruising NZ, a local cruiser resource center. Moore noted Tutukaka Marina’s location on the northern tip of the country directly facing Tonga made it especially vulnerable. Between eight and 10 boats were reportedly sunk, and many more sustained damage. The docks in the marina sustained extensive damage as well.
Similarly, 30 miles to the north, Indico Bay was also hosting a number of cruisers taking shelter from the storm. Among them were Greg Campbell and Mandy Davies on their 42ft Roger Simpson catamaran. “If we had known we were going to be getting tsunami surges, we would have gone out to deeper water. We would have been in a much better position there than in the bay we anchored in,” Davies said. According to Davies, some neighboring monohulls relocated to open water, but Davies and Campbell chose to stay. In all the surge in Indico Bay lasted about four hours.
On the other side of the Pacific, the coast of California also saw a number of boats damaged. In Ventura, boats were capsized in their slips or set adrift by currents strengthened by the surge. Santa Cruz saw the surge come in during high tide and then remain for over 24 hours. Other instances of disturbed tidal patterns were reported as far north as British Colombia.
Although tsunamis are difficult to detect offshore, they build as they travel with speeds that depend on the depth of the ocean. When they hit the shallow water surrounding land, the waves slow down and build in severity, creating large surges, causing significant amounts of damage far away from the epicenter of the disaster.