September 29, 1869 Tsunami: SW England, United Kingdom

Cornwall and Scilly Isles 1869. At Penzance and the Isles of Scilly, unusually high waves arrived between 0600h and 1000h on the morning of the 29 September 1869. The period of these waves was 20 minutes with a wave amplitude of about 5ft (~1.5m). Dawson et al. (2000) mentions that …there is at present no satisfactory explanation for these coastal changes. The weather report in The Times (1869) states that there was a thunderstorm at Portsmouth at 1800h on the 29th, which could have caused a meteotsunami earlier in the day before reaching Portsmouth. The Times (1869) also reports that The sea is disturbed at the entrance to the English Channel. It is uncertain what caused this disturbance, with only distant thunderstorms reported. Therefore, it appears most likely to be seiching, but what caused this is not clear. (reference #14269)

There was expectation of particularly large high tides on 6th October but would seem that the events of a week earlier were a surprise. The fact that the events were recorded both the English Channel and in the Bristol Channel and that that the first observation was frequently the sea receding make it less likely it was a meteotsunami. However the difference in the time the event was observed from west to east imply that it could not be a tsunami and that a meteotsunami is a more likely explanation. There are no earthquakes noted that could be associated with this event. This is considered a non-tsunami event. (reference #14326)