This is just some random thoughts after the news from Japan, hiking the Taroko National Park in Taiwan, driving with the stop train on the Coast Line in Taiwan, studying chinese, and being away from Computers for a day or two.
My idea for the tsunami would be something like an instant balloon. In Taiwan every floor has an emergency exit through the window and a device to use to safely get to the ground, there is also the famous lantern festival were hundreds of them fly to the sky. So in my idea groups could board an emergency balloon and escape the water, and some minutes later land on the more calm water.
Angelique's idea was having a transparent Tsunami Ball like structure. This way one would float on the water and the structure would be strong enough to withhold the enormous pressure the moving water has.