How long will you be in Japan? I don't know too much about the hills in Hiroshima, but its way south, so I wouldn't think there's gonna be much going on down there for a little while. We're only just getting the first few hills opening up in Hokkaido this weekend, and there's not going to be the famous Japanese pow for another few weeks.
Realistically, I'd say not worth bringing skis. Maybe bring boots, but even then, its alot of weight to be carrying around with you.