There has been at least one previous major recorded event, in 1607. As you will see in the accompanying articles, there has been considerable argument and speculation about the cause–was it a tidal surge, or was it a tsunami? The jury appears to have returned a verdict: it couldn’t have been a tsunami, as similar disturbances occurred on the east coast of England, indicating that it was associated with a storm crossing the country from west to east. Besides, a tsunami would have caused damage along the west coast of Wales, Cornwall, etc., and no such damage was recorded. So, not a tsunami…but nonetheless a pretty serious event, by all (that is, very few) accounts…and it does appear to have been a storm tide/storm surge. Which, after all, is described as being “tsunami-like,” generally implying a significant wavefront… and, eyewitness accounts of the disaster told of "huge and mighty hills of water" advancing at a speed "faster than a greyhound can run.”
Curiously, major events seem to recur every 100 years or so: after the Great Flood of 1607 came the great storm of 1703, waves came 4 feet (1.2 m) over sea walls; sea wall breached in 1799, filling Axe valley with sea water; 1919, 70,000 acres (283 km2) inundated with sea water, poisoning the land for up to 7 years.
And it appears that storm surges occur not infrequently, but cause no particular problems, since they do not coincide with a high spring tide: it is this coincidence that leads to disastrous events. One possible cause of the infrequency of events is the occasional occurrence of an unusual shift to the south of the jet stream, which scientists are finding may be related to the somewhat unpredictable El Nino phenomenon –see also Horsburgh, K. and Horritt, M. (2006), The Bristol Channel floods of 1607 –reconstruction and analysis. Weather, 61: 272–277. doi: 10.1256/wea.133.05
Horsburgh, K. and Horritt, M. (2006), The Bristol Channel floods of 1607 –reconstruction and analysis. Weather, 61: 272–277. doi: 10.1256/wea.133.05