Japan: Tropical Depression Shanshan weakening as it tracks eastward across Shikoku Island as of late Aug. 30 /update 9

Tropical Depression Shanshan is tracking eastward across Shikoku Island as of late Aug. 30. As of 21:00 JST, the system's center of circulation was approximately 46 km (29 miles) south-southeast of Iwakuni, Yamaguchi Prefecture. Forecast models indicate that the system will track eastward across Shikoku and the Kii Channel through Aug. 31 before making another landfall on Honshu Island over southern Wakayama Prefecture during the late afternoon. Shanshan will continue to weaken further as it moves east, likely turning to the northeast late Aug. 31 and ultimately dissipating over Nara Prefecture on Sept. 1.

As of early Aug. 31, the Japan Meteorological Agency (JMA) had issued various advisories and warnings for heavy rain, flooding, strong winds, high waves, and landslides. Red advisories (Warning) for heavy rains, in some cases accompanied by Purple advisories (Emergency Warning) for landslides, are in effect for prefectures in northeastern Kyushu, far southwestern Honshu, northern Shikoku, and parts of south-central Honshu, with lower-level yellow heavy rain advisories in place for most of the rest of the country. The heaviest rainfall of 30 cm (12 inches) is forecast for Hiroshima through Aug. 31. Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Millions of people are under evacuation orders. Authorities have issued black emergency safety evacuation orders (the highest level on a five-tier scale) for Kyushu Island. Some lower-tier evacuation orders remain in effect for parts of central Japan, while officials have also evacuated tens of thousands of people in Tokyo. Authorities have also issued a Level 4 warning for the Meguro, Nogawa, and Sengawa rivers in Tokyo due to record rainfall and swelling water levels.

As of late Aug. 30, the storm system has caused at least four fatalities due to landslides, with three deaths occurring in Aichi Prefecture when a landslide buried a house, and another fatality reported from a collapsed home in Tokushima Prefecture; additionally, over 100 people have been injured, many from broken glass and debris as the storm brought record rainfall and strong winds across regions including Kyushu and Shikoku. Over 139,000 households in Kyushu and more than 2,650 households across the Kanto region previously remain without power; additional power disruptions are highly likely in the affected areas and other parts of Japan.

Shanshan has caused significant related disruptions to air travel, with Japan Airlines (JAL) and All Nippon Airways (ANA) canceling 1,127 domestic flights until at least the end of Aug. 30. Other major airlines have grounded hundreds of domestic and international flights due to the storm. Additionally, officials have suspended numerous Shinkansen bullet train services in Japan, including Hakata, Hiroshima, Kyushu, Nagoya, Osaka, and Tokyo. Further delays and cancellations are likely to continue through early September.

Sustained heavy rainfall could trigger flooding in low-lying areas and those with easily overwhelmed drainage systems. If weather conditions prove hazardous, localized evacuations, flash flooding, and landslides are possible.

Inclement weather could trigger localized business, transport, and utility disruptions and render some bridges or roadways impassable. Additional flight disruptions at regional airports and temporary port closures are also possible. Stagnant pools of water during and after flooding may increase the incidence of insect- and waterborne diseases, such as dengue fever, cholera, and malaria. Exposure to raw sewage and other hazardous materials mixed with floodwaters poses a serious health threat.