I don't know about how Japan sets up their evacuation sites, but most of the time when evacuation centers were announced in the brief time I was in NOLA and then also growing up in HI (2 hurricanes in my lifetime for HI), they always tell you to bring your own supplies because water and food won't be provided. In my hawaii neighborhood, the response both times was to cook as much rice as possible in the time before the storm comes. With Iniki, after the storm destroyed Kauai, we had a fun block party to eat all the rice with other food items.
I personally don't know how to evacuate because like Annettehala, when you grow up on an island, you really have no options in terms of evading a storm other than having it miss you. And schools are the only sites to go to. We have a civil defense system in hawaii that is used and can be heard if you lack power. They test the siren once a month. We happen to live near enough that it's super loud. I guess if you get bombed by enemies, it's worthwhile to have a warning system that can be heard anywhere on the island for future attacks.
Incidentally, Ivan taught me how to evacuate the fastest way - airplane with your car at the top of the parking structure. But I was so unsure of whether or not to drive to lafayette to stay with friends, try to drive to houston, fly to houston, fly home, fly to oregon, fly to calif (where I ultimately went). And it's extra hard when the airlines jack up the prices cause they know folks are desperate to leave. At least that's what I noticed on orbitz.com. It would be nice to not charge and just fill the planes to capacity to aid the evacuation to help those with limited funds get out quickly.
Simple words to live by...
When someone annoys you, it takes 42 muscles to frown, but it only takes 4 muscles to extend your arm and whack them on the head.