Japan: Tropical Depression Shanshan weakening as it tracks eastward across Wakayama Prefecture as of early Aug. 31 /update 10

Tropical Depression Shanshan is tracking eastward across Wakayama Prefecture as of early Aug. 31. As of 12:00 JST, the system's center of circulation was approximately 322 km (200 miles) east-southeast of Iwakuni. Forecast models indicate that the system will exit into the Philippine Sea over the coming hours before turning sharply to track northward through early Sept. 1. Shanshan is forecast to make another landfall over eastern Mie Prefecture the afternoon of Sept 1 before weakening and dissipating over the northern part of the prefecture late Sept. 1. Some uncertainty remains in the track and intensity forecast, and changes could occur in the coming days.

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. Purple (highest level on a three-tier scale) landslide warnings are in place across southern Gifu, western Iwate, Kanagawa, northern Mie, southern Saitama, Shizuoka, and Tokyo prefectures. The heaviest rainfall of 30 cm (12 inches) is forecast for the Hokuriku region through early Sept. 1. Authorities will likely issue new warnings or update existing advisories throughout the system's progression in the coming days.

Millions of people were under evacuation orders at the height of the storm. Purple evacuation orders (the second highest level on a five-tier scale) remain in place for Aichi, Gifu, Kanagawa, Mie, southern Saitama, Shiga, Shizuoka, and Tokyo prefectures. As of early Aug. 31, the storm system had caused at least six fatalities, including three deaths occurring in Aichi Prefecture when a landslide buried a house. 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 were previously 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 thousands of domestic flights since Aug. 27. Other major airlines have grounded hundreds of domestic and international flights due to the storm. Authorities have suspended all services on the Tokaido Shinkansen between Mishima and Nagoya stations, between Gifu-Hashima Station in Gifu Prefecture and Maibara Station in Shiga Prefecture, and all direct services to the Sanyo Shinkansen Aug. 31, as well as between Mishima and Nagoyas stations Sept. 1. Officials halted services on the Tokaido Shinkansen between Tokyo and Mishima stations early Aug. 31. However, operations will likely resume around 12:00 Aug. 31. A reduced number of trains are operating on the Sanyo Shinkansen and on the Tokaido Shinkansen between Tokyo and Mishima stations and between Nagoya and Shin-Osaka station Aug. 31. Some sections of the Higashi Kyushu, Oita, Tomei, and Shin-Tomei expressways are closed. Further delays, closures, and cancellations will likely 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, rendering 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.