21 Dec 2021 | 04:37 PM UTC
Japan: Severe weather forecast across northern, central, and far southern regions through at least Dec. 22
Severe weather forecast across northern, central, and far southern Japan through at least Dec. 22. Disruptions possible.
Event
Heavy snow, thunderstorms, strong winds, and large waves are forecast in parts of northern, central, and far southern Japan through at least Dec. 22. Lightning and tornadoes are possible in northern areas due to the unstable weather; the combination of strong winds and snowfall in Hokkaido Prefecture is likely to lead to blizzard and hazardous travel conditions in some areas. As of late Dec. 21, the Japan Meteorological Administration has issued the following warnings:
Red snowstorm warnings: Hiyama, Ishikari, and Rumoi regions of Hokkaido Prefecture.
Yellow heavy rainfall, gale, snowstorm, heavy snow, thunderstorm, 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.
Hazardous Conditions
The stormy weather could produce rounds of heavy precipitation (including rain and snow), strong winds, and isolated thunderstorm activity. 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 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.
Transport
Floodwaters and related debris may render some bridges, rail networks, or roadways impassable, impacting overland travel in and around the affected areas. 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 if strong winds trigger hazardous sea conditions, impacting freight and passenger maritime traffic. Flooding or 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. 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.
