Meanwhile, by the end of this week until this weekend, another significant snowfall is likely to occur in the mountains of central and northern Japan with another three to five feet for some.
We’ll put this one under the heading “just when you think it can’t get any worse.”
Extreme snowfall is accumulating to record depths
Along the central west coast of Honshu, several places recorded astronomical amounts of snowfall due to a synergistic combination of cold air and humidity. In Takada, on the west coast of Niigata Prefecture, more than six feet of snow fell in three days. This will be equivalent to an inch of snow that falls every hour for 72 hours straight.
Hijiori, the recipient of several bouts of heavy snowfall over the past few weeks, had 1
To add insult to the injuries, this most recent storm also caused winds of nearly 100 miles per hour as it crossed the nation. The huge amount of snowfall has also raised fears of avalanche potential across the region.
A case of meteorological deja vu
If you think you’ve heard this story before, you’re right. Places on Japan’s snowy side have been hit by two other major snowstorms this winter, each producing more than seven feet of snow.
Japan has a reputation as one of the snowiest places on the planet; In fact, tourists from all over the world flock to the Tateyama Kurobe Alpine Route, which runs through the Hida Mountains in central Honshu to see the snow corridor that builds each winter season.
Factory for extreme snowfall
Japan is located along the Asian continent, separated by the relatively warm waters of the Sea of Japan. During the winter season, the warm ocean current of Kuroshio maintained the water temperature in the 50s and 60s. At the same time, some of the coldest air in the Northern Hemisphere is regularly carried east with prevailing winds outside Siberia, crossing the Sea of Japan.
As the cool air crosses the soft waters, it heats up and flows in with a huge amount of moisture; the air rises and condenses to make clouds and snow, its moisture eventually being deposited by wind in Japan like snow. This process, known as ocean or sea snow, is just like snow with a lake effect that happens near large lakes every winter.
Japan’s mountain ranges help cause upward movement in snow clouds, resulting in a very efficient snowmaking machine.
What makes ocean snow so fertile?
Ocean snow in the Sea of Japan is often much more intense and exists on a larger scale than what we find in the Great Lakes. Unlike most snow events in the Great Lakes, the structure of these ocean-effect snow strips is not always parallel to the prevailing wind direction. Sometimes the strips can be oriented diagonally or even perpendicular to the wind – but still lead to a lot of snow.
The secret of these epic snowfalls is not just how much snow falls, but the duration of the storms. In most parts of the world, once the main low-pressure system responsible for a snowstorm has receded, conditions usually improve. But in the case of the ocean effect of the ocean, as long as there is cold air crossing these warm waters, the snowfall can continue. This happened again over the weekend, with snowfall lasting up to three days in some places.
If the wind is constantly blowing from the same direction, snow strips parallel to the wind can be parked on the same area for hours or days, “flooding” places with constant heavy snowfall. It’s like “training thunderstorms” in the United States or repetitive, suspended bands of heavy rainfall that can cause flooding during the warm season.
The meteorological radar shows very strong levels of precipitation, which suggests some high, bubbling storm clouds. The storms also produced thunderstorms.
But what distinguishes snowfall in Japan this winter from other years? A combination of factors is at play.
The winter was colder than normal in East Asia, including northeast China and the Korean Peninsula. This cold air is essential for nourishing the snow with an ocean effect.
At the same time, several “low-pressure runways” created a favorable wind flow for prolonged cold temperatures above the waters to increase Japan’s snowfall potential during the three events.
Meanwhile, there is no immediate end to the record snowfall. The latest one-month snow forecast from the Japan Meteorological Agency suggests the chances of near-normal snowfall for Japan’s coastal areas – so there are certainly many more opportunities to add to the already incredible snowfall season.
Matthew Cappuccino contributed to this article.
Tom Niziol recently retired as a winter weather expert on the Weather Channel after a 32-year career at the National Weather Service in Buffalo.