An expert panel of Japan's Meteorological Agency says jet streams and a polar vortex were responsible for the record snowfall along the coast of the Sea of Japan this winter.
The agency says temperatures remained low nationwide between December and February. It says the average temperature in western Japan was more than one degree Celsius lower than the seasonal average -- and the lowest in about 30 years.
Record snow was also reported along the coast of the Sea of Japan. In early February, the accumulated snow in Fukui City exceeded 1.4 meters. That's the highest since 1981.
The panel says the polar and subtropical jet streams traveled south near Japan. It says that's why a strong, cold air mass from the north moved toward the country and a winter weather pattern grew stronger. The panel says the La Nina phenomenon may have had some impact on the course of the subtropical jet stream.
La Nina is a weather condition that occurs when sea surface temperatures fall below average in the Pacific near the equator off Peru.
The panel says a massive low-pressure system from the North Pole, called a polar vortex, also moved south and approached Japan.
According to NHK World Meteorologist Sayaka Mori, the shift in the jet streams and polar vortexes also took aim at other parts of the globe this winter.
From late December to early January, eastern North America endured one of the most frigid weather on record. Erie, Pennsylvania experienced the snowiest Christmas on record and New York City had the coldest New Year’s Eve in 100 years. Tallahassee, Florida had the first snowfall in 28 years and a couple of sharks were found dead on a beach in Massachusetts. Experts say they were possibly killed by cold shock. Toronto, meanwhile, recorded minus 23 degrees Celsius, shattering a 59-year-old record. In February, another polar vortex targeted the western United States, bringing the lowest temperatures in history to Los Angeles and blizzard conditions to the higher elevations in California.
At the same time, Europe was suffering from a deadly cold wave dubbed “the Beast from the East”. Many areas had record low temperatures and historic snow, resulting in dozens of deaths. Days of freezing temperatures pushed the wholesale gas prices to their highest level in a decade in the UK. The heaviest snow since 1982 hit Dublin, Ireland, causing a traffic chaos. Areas along the Mediterranean coast such as Nice, Corsica, Barcelona and Naples experienced rare snow. In Rome, 10cm of snow piled up, making it the deepest in 6 years and the largest for the time of year. In Vatican City, many people were seen enjoying snowball fight in St. Peter’s Square.
While the polar vortexes brought the Arctic chill to Asia, Europe and North America, warm air flowed into the North Pole, pushing temperatures to the unprecedented levels. The average temperatures over the Arctic region averaged several degrees higher than normal this winter. The warm weather resulted in a rapid ice melt. The average Arctic sea ice coverage in January became the smallest for the month since record keeping began in 1979.