be prepared, and have provisions to GO UP. if if sends the wave you will have 6-7hrs possibly, but most of the flooding will be BELOW street level and 1-4 floors POSSIBLY more.. but GO UP TO THE ROOF. I would want PFD's of some type and possibly a ROPE to tie off to something on the roof in case it consumes the building you are on top of. It should only damage the outlying buildings, but it will flood the entire city. BEING PREPARED is all you can do. then fire that sucker up!
o7