Japan's Meteorological Agency is warning of heavy snowfall in many parts of the country during the New Year's holidays, with the authorities pointing out the possibility of disruptions to transportation networks and blackouts. People are advised to be on the lookout for snow falling from roofs and avalanches.
The severe weather is due to an unusually cold air mass over Japan.
Japan's Meteorological Agency said snow fell on Thursday in mountainous areas from the northern prefecture of Hokkaido to the northern part of Kyushu in the southwest.
Weather officials caution that the cold air mass is expected to strengthen an atmospheric pressure pattern that will bring heavy snowfall.
They warn that through Thursday night, snowfall will become heavier, especially on the Japan Sea side of the southern and central parts of the main island of Honshu.
Weather officials say the snowfall may continue through Saturday on the Sea of Japan coast of the north and northeast of the country.
The winter weather has already disrupted transportation.
Services on part of the Yamagata Shinkansen bullet-train line in the northeast will be suspended from Thursday evening through New Year's Day.
Japan Airlines has cancelled 91 flights, including many scheduled to take off from or arrive at Tokyo's Haneda hub and Osaka airport on Thursday.
All Nippon Airways has cancelled 52 flights for Thursday.
Airlines and other transport providers are calling on travelers to check for the latest information as there may be more cancellations.