The Plymouth tsunami of June 1811

With the 10th anniversary of the Boxing Day Tsunami this year it has often occurred to me whether the British Isles has suffered from a similar catastrophe in centuries gone by.

The 'Extraordinary Phenomenon' reported in the Morning Post, Wednesday, June 5, 1811
The ‘Extraordinary Phenomenon’ reported in the Morning Post, Wednesday, June 5, 1811

With such a vast coastline it is certainly possible but written records of any events seem to be scarce. An entry in Luke Howard’s Climate of London, however, suggests that a phenomenon very similar to what happened in Asia in 2004 happened on our shores.

An entry on May 31, 1811, in Howard’s diary describes an “Agitation of the sea at Plymouth” that began at 3am – the sea fell instantly 4ft and immediately rose 8ft. “Universal consternation” pervaded the whole port, vessels in Catwater were thrown about in the greatest confusion with many dragging their anchor; some drifted and several lost their bowsprits and yards.

At 6.45am the sea rose to the height of 11ft and again receded. At 9.30am the tide suddenly stopped and suddenly ebbed 6 inches. At 10.30am it ebbed again in the same manner and then flowed to high water.

At the time it was noted that two gales from the SSW and E preceded this phenomenon but at the time it happened the wind was light from the SSW.

A few days later, on June 8th, the tide was again seen to flow and ebb several feet in as many minutes which continued at intervals over 4 or 5 hours. Immense swells were seen to flow into the harbours of Sutton Pool and Catwater at a rate of 4 knots an hour. During the time of the boar thunder and lightning was “excessive”.

These events coincided with a volcanic eruption near the shore of Ferraria, São Miguel, creating the short-lived Sabrina Island named after the British frigate HMS Sabrina, whose captain, Commander James Tillard, first identified the island and claimed it for the United Kingdom. The eruption caused destruction to many homes. The islet itself disappeared in the following years.

The event isn’t on record as being a tsunami but the symptoms seen in Plymouth all those years ago are similar, albeit on a much smaller scale, to those seen across Asia in 2004.

Could a tsunami affect the UK in the future? The British Geological Survey says not.



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