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13 Aug 2021 | 02:50 AM UTC

Japan: Severe weather likely in western and central regions through at least Aug. 16 /update 1

Severe weather forecast in parts of western and central Japan through at least Aug. 16.

Warning

Event

Further thunderstorms with heavy rainfall, strong winds, landslides, and possible flooding are forecast across Kyushu, western and central Honshu, and Shikoku through at least Aug. 16. The Japan Meteorological Administration has issued the following warnings:

  • Black (the highest level on a four-tier scale) heavy rain emergency warnings: Southern Hiroshima Prefecture.

  • Purple (the second-highest level on a four-tier scale) warnings for landslides due to heavy rain: Fukuoka, northern Hiroshima, northern Ishikawa, western Kagoshima, Kumamoto, eastern Nagasaki, southwestern Niigata, northern Oita, Saga, and western Toyama prefectures.

  • Red alerts for heavy rainfall, flooding, and landslides: Western Ehime, eastern Fukui, eastern Fukushima, the rest of Ishikawa, the rest of Kagoshima, the rest of Kumamoto, central Kochi, Miyazaki, northern Nagano, the rest of Nagasaki, northern Nara, the rest of Oita, Okayama, northern Shiga, Shimane, Tokushima, Tottori, the rest of Toyama, and western Yamaguchi prefectures.

  • Yellow heavy rain, thunderstorms, flooding, and landslide advisories: The rest of the affected area.

The heaviest rain is likely in Kyushu, Shikoku, as well as the Kansai Region, where up to 30 cm (12 inches) of rainfall is possible, while up to 25 cm (10 inches) of rainfall is probable in the Kanto, Koshin, and Tokai regions through at least early Aug. 14. In the Chugoku Region, up to 20 cm (8 inches) of rain is forecast. Officials could update and possibly extend the coverage of weather alerts over the coming days.

The Japan Meteorological Administration has issued Level 4 (the second-highest level on a five-tier scale) flood risk warnings for Gonokawa River in Hiroshima Prefecture due to high water levels in the river that would likely result in flooding. Additionally, Level 3 flood risk warnings are in place for Kuma River in Kumamoto Prefecture and Netani River in Hiroshima Prefecture.

As of early Aug. 13, authorities have issued Level 5 (the highest level) evacuation orders for Kumamoto Prefecture, affecting at least 10,921. Level 4 (the second-highest level on a fiver-tier scale) evacuations orders are also in effect for at least 2,760,484 elderly, including at least 653,229 from Fukuoka, 5,149 from Hiroshima, 165,194 from Kagoshima, 465,875 from Kumamoto, 1,098,409 from Nagasaki, 86,433 from Oita, and 286,195 from Saga prefectures due to severe weather and the risk of landslides.

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
As of early Aug. 13, some trains on the Kyushu Shinkansen are still delayed or suspended. Multiple railways and train lines are still experiencing disruptions, with trains suspended or delayed due to heavy rain. 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 Philippine Sea, East China Sea, and the Sea of Japan 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.

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