Ocean Effect Snow Makes Japan the Snowiest Place on Earth

John Hopewell
Published: March 6,2017

A police officer rides a bicycle on a snow covered field in front of the Imperial Palace in Tokyo.
(YOSHIKAZU TSUNO/AFP/Getty Images)

When most people think of Japan they conjure up images of raw fish on rice or karate. But when hardcore skiers and snowboarders think of Japan their minds drift to snow, and lots of it. Thanks to “ocean effect” (also called “sea effect”) snow and mountains reaching 10,000 feet, hundreds of inches of powder are dumped along the northwest side of Japan every winter. It is estimated that up to 1,500 inches falls in the highest terrain, making it arguably the snowiest place on Earth.
Sukayu Onsen in Aomori Prefecture, sitting at an elevation of 2,900 feet, collects more snow every year on than any other official reporting station in the world. In a typical winter observers record a mind-boggling 695 inches. But ocean effect snow also pummels large cities at sea level. Every year the two million residents residing in Sapporo have to cope with around 20 feet of the white stuff. And when the snow machine really gets cranking, intense snowfall rates can occur – 68 inches once fell in a 24-hour period in Tsukayama.

Japanese wild monkeys known as 'snow monkeys' bathe in a hot spring at the Jigokudani Wild Monkey Park in Yamanouchi town, Nagano prefecture, Japan.
(YASUYOSHI CHIBA/AFP/Getty Images)

So what exactly is ocean effect? It’s created by the same process as lake effect snow except the ocean is the moisture source. Japan is an island, to the east lies the vastness of the Pacific Ocean. To its west is the Sea of Japan, and beyond that is freezing cold Siberia. In the winter when frigid Siberian air masses cross the relatively warm Sea of Japan, an incredible amount of moisture evaporates from the surface of the ocean forming clouds. Eventually these clouds start to precipitate, usually in the form of snow. And when they encounter the formidable Japanese Alps and are forced higher into the atmosphere, the mountains wring out everything they’ve got.Japan is not the only place in the world that experiences ocean effect snow. The northern coast of Turkey can see several feet of snow generated by cold winds blowing over the warmer Black Sea. Istanbul has at least one ocean effect snow event every year. And the east coast of England can get in on the action when cold continental air from Europe pours in over the unfrozen North Sea. The phenomenon can also form in the open ocean and not impact land at all. This happens when cold air blows off the east coast of North America and interacts with the Gulf Stream.
In 1927 a world record settled snow depth of 465 inches was measured on Mt. Ibuki. That’s as tall as a four story building. There is so much snow that the Tateyama Kurobe Alpine Route, which is kept open with snow blowers tunneling all winter, has become a tourist attraction. And if you want to see it for yourself, peak season is January to March.

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