Philippines: Adverse weather forecast across parts of central and northern Luzon Island through at least Oct. 15

Event

A combination of weather systems are expected to bring adverse weather conditions to parts of central and northern Luzon Island through at least Oct. 15. The Philippine Atmospheric, Geophysical, and Astronomical Administration (PAGASA) has issued a weather advisory due to the presence a shear line and a low pressure system (named tropical depression Maymay by PAGASA) located to the east of Luzon. The weather systems are forecast to bring moderate to heavy rainfall to Cagayan, Isabela, Batanes, and Apayao provinces Oct. 11-12, as well as light to moderate rainfall to Abra, Kalinga, Mountain Province, and Ilocos Norte. The heavy downpours could trigger flooding and landslides in parts of the affected areas. A second low pressure area further to the east in the Philippine Sea is forecast to develop into a tropical storm and approach the far north of Luzon by Oct. 15.

As of Oct. 11, PAGASA have issued the following flood advisories across the affected area:

• Severe flood advisory (the second-lowest level on a four-tier scale): Isabela, Nueva Vizcaya, and Quirino provinces in Cagayan Valley Region; and Aurora and Zambales provinces in Central Luzon Region.

• Moderate flood advisory: Abra, Apayo, Benguet, Ifugao, Kalinga and Mountain provinces in Cordillera Administrative Region; and Ilocos Norte, Ilocos Sur, La Union, and Pangasinan provinces in Ilocos Region.

Due to the presence of tropical depression Maymay, PAGASA has issued Tropical Cyclone Wind Signal No. 1 (level 1 out of 5) for Isabela, Quirino, Nueva Vizcaya, Aurora, Nueva Ecija, and far northern Quezon (including the Pollilo Islands) provinces. The system is expected to strengthen as it tracks westward towards the east coast of central Luzon before making landfall late Oct. 12-early Oct. 13. The storm is forecast to weaken rapidly and then dissipate after making landfall.

Officials could update and possibly extend the coverage of weather alerts over the coming days.

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 heavy rainfall has saturated the soil.

Authorities could issue mandatory evacuation orders for flood-prone communities over the coming days. 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. 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, 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

Philippine Atmospheric, Geophysical, and Astronomical Administration (PAGASA)