Philippines: Adverse weather forecast across most of the Philippines through at least Oct. 7 /update 2

Event

Heavy rainfall, thunderstorms, strong winds, and possible flooding are forecast across most of the Philippines through at least Oct. 7 due to Tropical Depression Lannie.

Additional rainfall is forecast over the Calabarzon and Central Luzon regions, as well as Metro Manila and Aklan and Antique provinces in the Western Visayas Region.

A red (second-highest level on a four-tier scale) flood alert has been issued for the Central Visayas Region for rivers and their tributaries in Bohol, Cebu, Negros Oriental, and Siquijor provinces. Orange (second-lowest level on a four-tier scale) flood alerts for rivers and their tributaries have been issued in the following areas:

• Bangsamoro Autonomous Region in Muslim Mindanao (BARMM): Basilan, Lanao Del Sur, Maguindanao, Sulu, and Tawi-tawi provinces

• Bicol Region: Albay, Camarines Norte, Camarines Sur, Catanduanes, Masbate, and Sorsogon provinces

• Calabarzon: Batangas, Cavite, Laguna, Quezon, and Rizal provinces

• Caraga Region: Agusan Del Norte, Agusan Del Sur, Dinagat Islands, Surigao Del Norte, and Surigao Del Sur provinces

• Central Luzon: Aurora, Bataan, and Zambales provinces

• Eastern Visayas: Biliran, Eastern Samar, Leyte, Northern Samar, Samar, and Southern Leyte provinces

• Mimaropa: Marinduque, Occidental Mindoro, Oriental Mindoro, Palawan, and Romblon provinces

• Western Visayas: Aklan, Antique, Capiz, Guimaras, Iloilo, and Negros Occidental provinces

• Zamboanga Peninsula: Zamboanga Del Norte, Zamboanga Del Sur, and Zamboanga Sibugay provinces

Yellow flood advisories are in place for most of Cagayan Valley, Cordillera Administrative Region, and Ilocos Region. Officials could update and possibly extend the coverage of weather alerts over the coming days.

As of early Oct. 6, authorities report that at least 12 people remain stranded in Calabarzon, Central Visayas, Eastern Visayas, Mimaropa, and Western Visayas regions after 77 ports were closed due to Lannie. At least 32 ports have since been reopened in Mimaropa and Western Visayas.

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 or a lack of 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, strong winds, 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 if strong winds trigger hazardous sea conditions. Flooding could block regional rail lines; freight and passenger train delays and cancellations are likely 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 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

Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA)