Japan: Adverse weather forecast across northern regions through at least Feb. 18

Event

Heavy precipitation (including rain and snow), rough seas, and strong winds associated with a storm system are forecast across portions of northern Japan through at least Feb. 18. The Japan Meteorological Agency (JMA) has issued red storm, storm surge, snow, heavy rainfall, and high waves warnings for Kushiro, Nemuro, Tokachi Chiho, Aomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, Niigata, Toyama, Chiba, and Kanagawa prefectures. Yellow advisories are in effect for floods, strong winds, avalanches, fog, high waves, storm surge, heavy rainfall, thunderstorms, and heavy snowfall across the affected area. Authorities will likely issue new alerts or update/rescind existing advisories as the winter storm transits the region over the coming days.

Hazardous Conditions
The system could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity across northern Japan. Where precipitation falls as rain, flash and areal flooding is possible. Such flooding is possible in low-lying communities near watercourses and other large bodies of water, as well as in urban areas with easily overwhelmed or a lack of stormwater drainage systems. Sites located downstream of large reservoirs may be subject to flash flooding after relatively short periods of intense rainfall.

Precipitation could fall as snow in the higher elevations over the coming days. Wind gusts could cause blowing and drifting snow; decreased visibility is likely in mountainous areas. Rain-induced landslides cannot be discounted in areas of elevated terrain; there is also the possibility of avalanches in mountainous areas where the snowpack has become unstable due to heavy snowfall. Power outages could occur throughout the affected area through at least Feb. 18.

Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected area. Flooding in urban areas could also result in significant traffic congestion. Heavy snow will likely make driving hazardous in some areas; authorities could implement temporary road closures or detours in such locations. Mountain passes and tunnels could be closed as a precautionary measure during periods of intense snowfall.

The disruptive weather will likely cause some delays and cancellations at regional airports. Authorities may temporarily suspend port operations along the Sea of Japan, Sea of Okhotsk, and Pacific Ocean if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding/snow could block regional rail lines; freight and passenger train delays and cancellations are possible in areas that see heavy rainfall and potential track blockages.

Disruptions triggered by inclement weather and resultant hazards, such as flooding or avalanches, could persist well after conditions have improved - it could take days before any floodwaters recede and/or officials clear debris. If there is severe damage to infrastructure, repair or reconstruction efforts may result in residual disruptions.

Advice

Monitor local media for weather-related updates and advisories. Confirm all transport reservations and business arrangements before traveling in the affected area through at least Feb. 18. Seek updated information on road conditions before driving or routing shipments through areas where severe weather is forecast; plan for possible supply chain disruptions throughout the affected areas. Stay away from elevated streams, creeks, and other watercourses that are prone to flash flooding. Do not attempt to navigate flooded roadways. Exercise caution in elevated terrain due to the threat of landslides, as well as mountainous regions where avalanches pose a threat. Charge battery-powered devices in the case of prolonged electricity outages.

Resources

Japan Meteorological Agency