Japan: Severe weather forecast over most of Japan through at least Dec. 19

Event

Heavy snow, blizzards, storms, strong winds, and large waves are forecast for most of Japan through at least Dec. 19. As of Dec. 17, the Japan Meteorological Administration has issued the following warnings:

• Red storm, snowstorm, and large wave warnings: eastern Aichi, western Akita, Fukui, southern Hokkaido, northern Hyogo, Ishikawa, Kagoshima, Kanagawa, northern Kyoto, western Nagasaki, Niigata, Oita, Shimane, Tottori, Toyama, western Yamagata, and Yamaguchi prefectures.

• Yellow gale, snow, storm, and large waves advisories: the rest of the affected area.

Authorities will likely issue new warnings or update existing advisories in the coming days; officials may issue evacuation orders if weather conditions persist or worsen.

Winter weather is forecast over northern and western Japan Dec. 18. Very strong winds with snow are likely along the Sea of Japan side of the country. Waves of up to 6 meters (20 feet) are forecast in the Chugoku, Kanto, Koshin, Hokuriku, Kinki, and Tohoku regions, and up to 5 meter (16 foot) waves are likely in Kyushu as well as Hokkaido and Tokai regions. Snowfall of up to 60 cm (24 inches) is forecast in the Hokuriku region and up to 50 cm (20 inches) of snow is likely in the Kanto, Koshin Hokkaido, and Tohoku regions through Dec. 18. Lesser accumulations are likely across Shikoku and northern Kyushu as well as Chugoku, Kinki, and Tokai regions. Through Dec. 19, 30-50 cm (12-20 inches) of snow is forecast across the Hokkaido, Hokuriku, and Tohoku regions, while 20-40 cm (8-16 inches) of snow is likely in the Chugoku, Kanto, Kinki, Koshin, and Tokai regions.

Hazardous Conditions
Sustained heavy rainfall could trigger flooding in low-lying communities near rivers, streams, and creeks. Urban flooding is also possible in developed areas with easily overwhelmed stormwater drainage systems. Sites located downstream from large reservoirs or rivers may be subject to flash flooding after relatively short periods of intense rainfall. Landslides remain possible in hilly or mountainous areas, especially where the soil has become saturated by heavy rainfall. Disruptions to electricity and telecommunications services are possible where significant flooding or landslides impact utility networks.

Transport
Floodwaters and debris flows may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around affected areas. Ponding on road surfaces could cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters. Severe weather could also trigger flight delays and cancellations at regional airports. Authorities may temporarily suspend port operations or close beach fronts along the North Pacific Ocean if strong winds trigger hazardous sea conditions. The Tokyo Bay Ferry connecting Kurihama in Yokosuka City, Kanagawa Prefecture and Kanaya in Futtsu City, Chiba Prefecture remains canceled as of morning Dec. 17.

Flooding could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track inundation. Authorities have suspended or delayed multiple trains in western Japan due to strong winds, heavy snow, and obstructions on the tracks.

Localized business disruptions may occur in low-lying areas; some businesses might not operate at full capacity because of flood damage to facilities, possible evacuations, and some employees' inability to reach work sites.

Advice

Monitor local media for weather updates and related advisories. Confirm all transport reservations and business appointments before travel. Make allowances for localized travel delays and potential supply chain disruptions where flooding has been forecast. Do not drive on flooded roads. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Japan Meteorological Administration