Japan: Adverse weather forecast across northern Honshu, Japan, through at least end June 16

Event

Thunderstorms with heavy rainfall and landslides are forecast across portions of northern Honshu, Japan through at least end June 16. The Japan Meteorological Administration has issued the following warnings:

• Purple (second-highest level on a four-tier scale) heavy rain and landslide warnings in western Fukushima and eastern Yamagata prefectures

• Orange warning (second-lowest) for heavy rain, flooding, and landslides for western Iwate Prefecture

• Yellow advisories (lowest) for thunderstorms, heavy rain, landslide, and flooding for the rest of the affected area

Officials could update and extend the coverage of weather alerts over the coming days. Local governments may issue evacuation orders if the threat of landslides increases, particularly for areas near cliffs or valley exits.

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 are 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 Sea of Japan and North Pacific Ocean if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas that see heavy rainfall and potential track inundation.

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