It's not in Japan, but check out this website for the American Avalanche Institute-
http://www.avalanchecourse.com/In their course descriptions, they have suggested readings and lists of texts and links that are all relevant.
Read up, dork-out on snow crystals until you have that stuff memorized inside and out. spend time in the field actually looking at snow... with a magnifying glass. Start paying attention to the behavior of snow. It is quite predictable. (though not reliable)
Also, study up on weather. I'm amazed at how many bc-prepared people I have met that don't pay attention to atmospheric pressures, clouds and changing temps. It's quite easy to predict tomorrow's snow crystals. It's also quite easy to predict how today's snowpack is changing at all depths.
mmmmm.... snow science... hoar.