Japan: Adverse weather forecast across Okinawa and far western Kyushu regions through at least April 15

Severe weather is forecast across parts of Okinawa and far western Kyushu regions through at least April 15. As of March 25, the Japan Meteorological Agency (JMA) has issued the following weather warnings across the affected area:

• Purple landslide warnings (the highest level on a three-tier scale): Okinawa Prefecture.

• Red heavy rain and landslide warnings: Okinawa Prefecture.

• Red flood warnings: Kume Island and central and southern Main Island in Okinawa Prefecture.

• Red storm warnings: Goto Islands in Nagasaki Prefecture.

• Yellow warnings: across the rest of the affected area.

Officials will likely issue new alerts or update/rescind existing advisories as weather conditions develop over the coming days.

As of early April 15, authorities have issued purple evacuation warnings (the second highest level on a five-tier scale for evacuation warnings) for tens of thousands of people in parts of Itoman, Naha, and Tomigusuku cities in Okinawa Prefecture due to the threat of landslides. Red evacuation warnings for elderly people and other vulnerable groups are in place for parts of Nanjo City and Yonabaru Town.

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 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 heavy rain has saturated the soil. Disruptions to electricity and telecommunications services are likely where significant flooding, landslides, or strong winds impact utility networks.

Floodwaters and debris flows will likely render some bridges, rail networks, or roadways impassable, impacting overland travel around affected areas. Ponding on road surfaces will likely cause hazardous driving conditions on regional highways. Authorities could temporarily close some low-lying routes that become inundated by floodwaters.

Severe weather will also probably trigger intermittent flight delays and cancellations at airports across the affected region, though these are unlikely to be severe or prolonged. Authorities will likely suspend port operations or close beach fronts temporarily if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely in areas with heavy rainfall and potential track inundation. Localized business disruptions will likely occur in low-lying areas.