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02 Jul 2021 | 03:39 AM UTC

Japan: Adverse weather forecast across southern and southeastern regions through at least July 3 /update 1

Heavy rainfall, strong winds, and possible flooding forecast across southern and southeastern Japan through at least July 3.

Warning

Event

Thunderstorms with heavy rainfall, strong winds, landslides, and possible flooding are forecast across southern and southeastern Japan through at least July 3. The Japan Meteorological Administration has issued purple warnings (the highest level on a three-tier scale) for heavy rainfall and landslides in Shizuoka Prefecture and the Northern Izu Islands. Additionally, orange alerts for heavy rainfall, flooding, and landslides are in place for Aichi, Chiba, Kanagawa, Nagano, Shizuoka, southern Wakayama, and western Yamanashi prefectures, as well as the Northern Izu islands in Tokyo Prefecture. Yellow heavy rain, thunderstorms, flooding, and landslide advisories are in effect for the rest of the affected area. Officials could update and possibly extend the coverage of weather alerts over the coming days.

Authorities have issued evacuation orders for 52,674 households and 124,038 people from Shizuoka Prefecture and 2,064 households and 3,771 people from Wakayama Prefecture due to the risk of landslides caused by heavy rain. There have been no reports of injuries or damage.

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 are 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 regional airports. Authorities may temporarily suspend port operations or close beach fronts along the East China Sea, Philippine Sea, and North Pacific Ocean 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.

Resources

Japan Meteorological Administration