It appears that like in a hurricane, even if your boat is securely fastened unless you are uptream of floating boats/ships/houses and other debris, damage is likely. I wonder what the relative force of all the debris is rising versus falling water heights.....because much is subsequently swept out to sea....

Portions of some of these are on tv...more than I have seen there appears below...

http://www.youtube.com/watch?v=4YPOK_3r8Dc&feature=

http://www.youtube.com/watch?v=4YPOK_3r8Dc&feature=

http://www.youtube.com/watch?v=SQTJy5mWejA&feature=