20 May 2021 | 11:01 AM UTC
Japan: Adverse weather resulting in flooding or landslides in southern and central areas likely through at least May 21
Heavy rain and thunderstorms could lead to flooding or landslides in southern, central Japan through at least May 21. Disruptions likely.
Event
Heavy rainfall, strong winds, flooding, and landslides are forecast across southern and central of Japan through at least May 21. As of May 20, the Japan Meteorological Agency has issued the following warnings:
Purple-level landslide warnings (the second-highest alert level on a five-tier scale) in place for portions of southern Ehime, Kagoshima, southern Kumamoto, Fukuoka, Nagasaki, and Saga prefectures.
Red-level heavy rainfall warnings (the third-highest alert level on a five-tier scale) in place for Nagasaki, Kagoshima, Saga, Kumamoto, Miyazaki, Oita, Fukuoka, Yamaguchi, Hiroshima, and Ehime prefectures.
Yellow-level thunderstorm and heavy rainfall warnings are in place for the rest of the affected area including Okinawa, eastern Kagoshima, southern and northern Miyazaki, Nagasaki, Fukuoka, Yamaguchi, Shimane, northern Hiroshima, Tottori, Okayama, Kagawa, Tokushima, Wakayama, Osaka, Kyoto, Fukui, Shiga, Hyogo, Mie, Fukui, Ishikawa, Gifu, Aichi, Shizouka, Tokyo, Chiba, Ibaraki, Saitama, Yamanashi, Nagano, Toyama, Ishikawa, and Niigata prefectures.
Officials could update and possibly extend the coverage of weather alerts over 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 or a lack of 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.
As of May 20, officials have issued evacuation warnings for southern Kumamoto prefecture, including Minamata City, Ashikita, Tsunagi, and portions of Amakusa City. Authorities could issue additional mandatory evacuation orders for flood-prone communities over the coming days. 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. 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.
