Here in mid-Missouri, we’re accustomed to seeing snowfall at least once each winter. What we aren’t used to is seeing more than roughly 20 inches of snow in a year. Parts of Japan however, picked up over 7 feet of snow within these past two weeks alone! This snowfall was caused by a natural phenomenon that impacts Japan almost every winter.
For any precipitation to occur, there must be moisture in the air. For us here in mid-Missouri, we often get our moisture from southerly winds pulling from the Gulf of Mexico. In Japan’s case, the moisture came from northwesterly winds pulling from the Sea of Japan. This is considered ocean effect snow. Ocean effect snow is when cooler air blows across a warmer body of water, drawing in moisture to the atmosphere.
To put things into a perspective that we are likely more familiar with, think of the Great Lakes. They often see huge amounts of snowfall along their shores, and that snow is formed in a similar way as ocean effect snow forms... cold wind over warm water.
So why don’t we see 7 feet of snow? Well, since we’re so far from the Gulf of Mexico, we don’t often see enough available moisture making its way to Missouri to even give us nearly as much snowfall. If the size of each arrow here shows how much moisture is available, you’ll see that a lot of moisture is lost on its way to mid-Missouri. We can only see so much snow with so little moisture available.
We have seen some great snowfall accumulation in the past, and it's a great possibility that we could see some more in the future. If you really want a shot to see great snowfall accumulations though, you’ll want to seek out places where ocean and lake effect snow are common.