Meanwhile, there is likely to be another round of significant snowfall in the mountains of central and northern Japan late this week out this weekend with three to five meters more on the way for some.
We file this under the heading “just when you think it couldn’t get any worse.”
Extreme snowfall stacks up to record depths
Along the central west coast of Honshu, several places recorded astronomical snowfalls due to a synergistic combination of cold air and moisture. At Takada, on the west coast of Niigata Prefecture, more than 6 meters of snow fell over a three-day period. This is equivalent to an empty snow falling every hour for 72 hours in a row.
Hijiori, the recipient of several periods of heavy snowfall in the last few weeks, had 1
To add insult to injury, this recent storm also produced winds up to nearly 100 mph as it crossed the nation. The huge total snowfall has also given rise to concern about avalanche potential throughout the region.
A case of meteorological deja vu
If you think you’ve heard this story before, you’re right. Places all over the snow country Japan have been hit by two other major snowstorms this winter, each producing more than 7 feet of snow.
Japan has a reputation as one of the most snow-capped places on the planet; it is well deserved. In fact, tourists from all over the world flock to the Tateyama Kurobe Alpine Route, which weaves through the Hida Mountains in central Honshu to see the snow corridor that builds each winter season.
A factory for extreme snowfall
Japan is located off the Asian continent separated by the relatively warm waters of the Sea of Japan. In the winter season, the warm Kuroshio ocean current keeps the water temperature in the 50s to low 60s. At the same time, some of the coldest air in the northern hemisphere is regularly transported eastward by prevailing winds out of Siberia and crossing the Sea of Japan.
As the cool air crosses the mild water, it is heated and infused with an enormous amount of moisture; the air rises and condenses to create clouds and snow, and its humidity is eventually deposited by tailwinds over Japan as snow. This process, known as ocean or garden effect snow, is like snow with effect with lake occurring off the great lakes every winter.
The mountain ranges in Japan help induce upward movement in snow clouds, resulting in a very efficient machine for making snow.
What makes snow with garden effect so productive?
Snow with garden effect in the sea of Japan is often much more intense and is found on a larger scale than what we encounter from the great lakes. Unlike most snow events in the Great Lakes, the structure of these snow-affected snow bands is not always parallel to the prevailing wind direction. Sometimes the bands can be oriented diagonally or even perpendicular to the wind – but they still result in lots of snow.
The secret behind these epic snowfalls is not only how hard the snow comes down, but the duration of the storm. Across most of the world, as the primary low-pressure system responsible for a blizzard moves away, conditions generally improve. But in the case of Japan’s garden effect, as long as there is a supply of cold air crossing the hot water, snowfall can continue. That’s what happened again over the weekend, with snowfall persistently spotting up to three days.
If the wind is consistently blowing from the same direction, snow bands parallel to the wind can park over the same area for several hours or days, “flooding” spots with constant heavy snowfall. It’s similar to “thunderstorm training” in the United States or repeated, stopped bands of heavy rain that can cause flooding in the hot season.
Weather radar showed very heavy rainfall speeds, suggesting some high, bubbling storm clouds. The storms also produced thunderstorms.
But what sets Japan’s snowfall this winter apart from other years? A combination of factors has been at stake.
The winter has been colder than usual in East Asia, including northeastern China and the Korean Peninsula. That cold air is conducive to nourishing snow with a garden effect.
At the same time, several low-pressure “storm tracks” have created a favorable wind current for prolonged cold temperatures above the water to maximize the snowfall potential for Japan during all three events.
Meanwhile, there is no immediate end in sight for the record-breaking snow. The Japanese Meteorological Agency’s latest snowfall forecast for one month suggests odds of almost normal snowfall in Japan’s coastal areas – so there are certainly plenty of more options to add to an already fantastic snowfall season.
Matthew Cappucci 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 office in Buffalo.