During the winter months (Dec-Mar) Japan is bombarded by low pressure systems that descend from the arctic and Siberia (Oct-Mar) giving cold dry air that picks up moisture over the Japan Sea deposits it as fresh Pow upon the Japanese alps. Unlike Europe the ranges are close to the ocean and the precipitation does not have to carry over long distances before hitting mountain ranges.It remains cold and dry depositing first on the coastal ranges and then the much higher inner alps. It does not have to be carried over and long distances in often fluctuating temperatures to be deposited like Europe's central alps.
So with powder an assumption the only other consideration is the height of your mountains and the steepness of the terrain.
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One week this(21Feb 09)
The next week this.(25Feb 09)
Still Dumping (27 Feb 09)
Typhoons.
Summer months (Aug-Oct) see the reverse pattern from the
West in the form of typhoons driven upwards over the
pacific via the Philippines.Giving a pattern of low
pressure systems that when they sit the correct distance
for a given length of time yields corduroy to the horizon.
August 20- Typhoon season
start
