Japan: Winter weather forecast over parts of Honshu and Hokkaido through at least Dec. 28 /update 1

Event

Winter weather, including heavy snow, is forecast across parts of Honshu and Hokkaido through at least Dec. 28. The Japan Meteorological Administration has issued red high wave warnings across far northeastern Hokkaido Prefecture through Dec. 27. Red heavy snow warnings are also in place across western Aichi, Aomori, southern Gifu, northern Kyoto, southern Niigata, and Shiga prefectures through Dec. 27. Yellow heavy snow advisories are in place across the rest of the affected areas through Dec. 28. 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.

Heavy snow is forecast from northern to western Japan, especially along the Sea of Japan coast. Heavy snow of 90 cm (35 inches) is likely across the Hokuriku and Tokai regions, while 80 cm (31 inches) of snow is forecast in the Kinki region through early Dec. 28. Lesser snow is forecast over the Chugoku, Kanto, Koshin, and Tohoku regions. Lightning and tornadoes are possible across the affected area through Dec. 28.

At least 1,540 households in Hyogo, Kyoto, and Shiga prefectures are without power due to the heavy snowfall.

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
The winter weather will likely cause ground and air transport disruptions over the coming days. Traffic and commercial trucking delays are possible along regional highways. Difficult and potentially dangerous driving conditions are also likely on secondary and rural roadways in the affected states as maintenance crews prioritize clearing major routes. Authorities could close stretches of highway if driving conditions become too hazardous. Parts of National Highway 8 and the Hokuriku, Isewangan, Mei-Nikan, Meishin, Tokai-Hokuriku, Tokai-Kanjo, and Shin-Meishin expressways are closed due to the heavy snow. Gusty winds may threaten to topple high-profile vehicles throughout the affected area. Severe weather could also trigger flight delays and cancellations at regional airports. Authorities have canceled at least 25 flights from Toyama Airport (TOY), 21 flights from various airports across Hokkaido Prefecture, and at least two flights between Osaka International Airport (ITM) and Kounotori Tajima Airport (TJH) in Hyogo Prefecture.

Officials may temporarily suspend port operations or close beach fronts along the Sea of Japan and the North Pacific Ocean if strong winds trigger hazardous sea conditions. 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 due to heavy snow. Tokaido Shinkansen is reducing speed between Shin-Osaka and Toyohashi stations in Aichi Prefecture due to the heavy snow, resulting in delays on the Sanyo Shinkansen.

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