I am in awe and horror at the videos that are coming now from everywhere. National Geographic is going to have a heck of a special when they get around to do it....
The Guardian has quite a selection (as many other do but at least they do not slobber over them with editorial comments). This one shows you the brute force of the water quite dramatically. You can actually see some people over a topsy turvied home, and a bus trying to escape the rising waters, I imagine with passengers on board (I think they made it but there is no way to tell for sure).
This video about the damages in one of the towns, what is left of it, with railroad as a picket fence now.
In this video you can hear the alarm system at first but clearly the images tell you that the alarm was, well, useless if you were unable to leave the street early enough..... some of the earlier part was shown a lot on TV but it pays to watch it completely, the horror of these people watching their city disappear sunks in, deeply.
The attitude of the surviving Japanese is extraordinary. In addition this video has some scenes of the day after that tell you how amazingly high the water rose in some areas.
But the video that got me was from the day after at Minamisanriku by the team from France 2 TV when they visited the pediatric ward, or rather, what was left of it. Yours truly, starting at 50sec, could not keep a dry eye. (warning, the French are so special that they do not use the standard video formats so your computer might ask you to download stuff).