17 Aug 2022 | 11:30 AM UTC
Japan: Adverse weather forecast across much of the country through at least Aug. 19 /update 7
Severe weather forecast across much of Japan through at least Aug. 19. Evacuations ongoing in multiple regions.
Event
Severe weather is forecast across much of Japan through at least Aug. 19. The Japan Meteorological Administration (JMA) has warned a weather front extending from a low pressure system will move over eastern and western Japan Aug. 18 and another low pressure system in the western Sea of Japan will move northeast over northern Japan. The weather systems will combine to bring heavy rainfall and thunderstorms from northern to western Japan throughout Aug. 18. Heavy rainfall will likely trigger rising river levels, flooding, and landslides in some areas. Storms may be accompanied by strong wind gusts, lightning, hail, and possible tornadoes.
Rainfall totals of around 18 cm (6 inches) in northern Kyushu Region, 15 cm (6 inches) in Shikoku and Tohoku regions, 12 cm (5 inches) in Chugoku, Hokuriku, Kinki, and Tokai regions, and 10 cm (4 inches) in Kanto and Koshin Region are expected late Aug. 17-late Aug. 18. Parts of northern Japan have experienced heavy rainfall in recent days and the saturated soil in these areas increases the risk of further flooding and landslides.
As of late Aug. 17, the JMA has issued the following warnings across Japan:
Purple heavy rain and landslides warnings (the highest level on a three-tier scale): Parts of Fukuoka and Saga prefectures in northern Kyushu Region.
Red heavy rain, landslides, and flood warnings: Parts of Hiroshima, Okayama, and Shimane prefectures in Chugoku Region; Ishikawa Prefecture in Hokuriku Region; Fukuoka, Kumamoto, Nagasaki, Oita, and Saga prefectures in northern Kyushu Region; Kyoto and Shiga prefectures in Kinki Region; and Mie Prefecture in Tokai Region.
Yellow heavy rain, flood, landslide, gale, high wave, storm surge, thunderstorm, and dense fog advisories: across much of the rest of Japan.
Authorities will likely issue new warnings or update existing advisories in the coming days.
As of late Aug. 17, authorities have issued evacuation orders in multiple areas due to adverse weather conditions. Evacuations have been ordered for around 400 people in Murakami City and 70 people in Sekikawa village in Niigata Prefecture; around 2,400 people in Wajima City and the whole of Anamizu Town in Ishikawa Prefecture; and for the whole of Kashima City and parts of Shiroishi Town and Ureshino City in Saga Prefecture. Evacuations for the elderly have been issued for parts of Aomori, Ishikawa, Shizuoka, Shiga, Kyoto, Hiroshima, Fukuoka, Saga, Nagasaki, and Oita prefectures. Further evacuation orders are likely to be issued by authorities due to the adverse weather forecast over the coming days; the latest evacuation information can be found here.
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
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 airports in affected regions. Authorities may temporarily suspend port operations or close beach fronts 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.
