i haven't read all of the responses regarding omiyage, but i would say it's not a huge thing if you don't bring anything from your home country. i bought some candy, but i didn't bring it with me on the first day. instead i brought omiyage from Tokyo and Kyoto where i had traveled before working. i only got 2 boxes of 16-18 sweets each, but it turns out that my first school was also a ridiculously tiny school, and i had brought enough to give to both all the teachers *and* all the students. hahaha.
i don't think that every school will expect you to give omiyage. it will certainly be appreciated if you do, but don't feel you have to go overboard. at my second school i was pretty good about buying for the 36-some teachers whenever i traveled (and i would individually distribute rather than leaving it in a public place, since it seemed that's what everyone else did). everyone seemed to be surprised rather than "i know you went on a trip, where the hell is my goodie?"
i've also noticed that at least at the school i just left, teachers would often buy omiyage just for their "bu" (teachers tend to sit in groups based on which grade they teach. 1-nenbu, 2-nenbu, etc.) rather than every single teacher in the staffroom. i bought it for everyone anyway because i had JTEs at each bu, and i'd often give to the office staff as well. it's not required, but it definitely helped me get to know the teachers, and many people would thank me for it even after the fact.
yeah the weather was pretty crazy, but it seemed to have died down recently. just rain, i can't hear/feel the wind shaking my apartment anymore. i don't get the impression it was dangerous, more of an inconvenience with stopped/delayed trains. at least where i live.
