The Great Flood of 1606

At nine o’clock on the clear morning of Tuesday, January 20, 1606 (1607)*,
a massive flood swept up the Bristol Channels, completely without
warning, devastating the countryside over 400 km and killing between
500 and 2000 people. A contemporary pamphlet called Gods Warning to His People of England  records the event: 

Then they might see & perceive a far of as it were in the Element, huge and mighty Hilles of water, tumbling one over another, in such sort as if the greatest mountaines in the world, has over-whelmed the lowe Valeys or Earthy grounds. Sometimes it so dazled the eyes of many of the Spectators, that they immagined it had bin some fogge or miste, comming with great swiftnes towards them: and with such a smoke, as if Mountaynes were all on fire: and to the view of some, it seemed as if Myliyons of thousandes of Arrowes had bin shot forth at one time, which came in such swiftnes, as it was verily thought, that the fowles of the ayre could scarcely fly so fast, such was the threatning furyes thereof. (quoted in the 400-year Bristol Flood Retrospective, a PDF document)

A site devoted to the history of Burnham-on-the-Sea, quotes another  contemporary source filled with "human interest stories." In the following excerpts,  a chicken and a cat (respectively) are credited with saving the lives of two children:

A maide child, not passing the age of foure years: it is reported
that the mother thereof, perceiving the waters to breake so fast
into her house, and not being able to escape with it, and having
no clothes on, set it upon a beame in the house, to save it from
being drowned. And the waters rushing in a pace, a little chicken
as it seemeth, flew up unto it [the child], (it being found in
the bosome of it, when helpe came to take it [the child] downe)
and by the heate thereof, as it is thought, preserved the childe’s
life

Another little childe is affirmed to have been cast uppon land in a cradle, in which was nothing but a catte [cat], the which was discerned as it came floating to the shoare, to leape still from one side of the cradle unto the other, even as if she had been appointed
steresman to preserve the small barke from the waves furie.

Some scientists believe the flooding was the result of high spring tides combined with a storm surge, and others believe it was a tsunami. Whatever the cause, the Bristol flood was one of the greatest natural disasters in British history. It occurred at just around the time that scholars were researching the King James Bible and Shakespeare was writing Antony and Cleopatra.

*The year was 1606 according to the calendar used at the time and 1607 according to the one we use now.