Japan: Severe weather ongoing nationwide as of Aug. 18 /update 5

Event

Heavy rains are ongoing across Japan as of Aug. 18. The Japan Meteorological Administration has issued the following warnings:

• Purple (the second-highest level on a four-tier scale) warnings for landslides due to heavy rain: Aichi, eastern Ehime, southern Fukuoka, northern Gifu, southern Hiroshima, Kagoshima, most of Kumamoto, southern Nagano, southern Okayama, Saga, Shizuoka, Tokushima, and eastern Yamanashi prefectures.

• Red warnings for heavy rainfall, flooding, and landslides: Eastern Aomori, western Ehime, Fukui, central Fukushima, the rest of Fukuoka, the rest of Gifu, the rest of Hiroshima, far southern Hokkaido, southern Hyogo, Ishikawa, southeastern Iwate, western Kanagawa, the rest of Kagoshima, the rest of Kumamoto, eastern Kochi, southern Kyoto, western and southern Miyazaki, the rest of Nagano, Nagasaki, southern Nara, northern Oita, Osaka, Saga, Shiga, northern Tochigi, eastern Toyama, northern Wakayama, western Yamanashi prefectures.

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

Adverse weather will likely continue in the coming days; authorities may expand evacuation orders if weather conditions persist or worsen.

Through late Aug. 19, the low-pressure system is likely to bring at least 20 cm (7.5 inches) of rainfall to southern Kyushu, 18 cm (7 inches) of rainfall to the Shikoku Region, 15 cm (6 inches) of rainfall to the Tokai Region, and 12 cm (4.5 inches) of rainfall to the northern Kyushu, Kinki, Kanto, Koshin, and Hokkaido regions. Shikoku Region is forecast to receive 10-20 cm (4-8 inches), and 10-15 cm (4-6 inches) of rainfall is likely for the Kinki Region from late Aug. 19 to late Aug. 20.

Authorities have ordered the evacuation of at least 2.6 million people from Aichi, Ehime, Fukuoka, Gifu, Hiroshima, Hyogo, Kumamoto, Kyoto, Nagasaki, Nagano, Niigata, Oita, Osaka, Saga, Tokushima, and Yamaguchi prefectures. At least 52 rivers in Fukui, Fukuoka, Gifu, Hiroshima, Kumamoto, Oita, Saga, Shiga, and Shimane prefectures, have overflowed in worst-hit regions; Kuma River in Kumamoto Prefecture is also in danger of flooding. Reports indicate around 23 people were injured. Additionally, landslides have killed at least four people, including three in Okaya City, Nagano Prefecture, and one in Unzen City, Nagasaki Prefecture, as of early Aug. 18. Reports also indicate damage to multiple structures and flooding of around 4,326 buildings. Officials will likely provide further updates on damage and casualties in the coming days.

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
Multiple railways and train lines in affected areas have experienced 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