HEAVY rainfall brought about by the southwest monsoon caused heavy flooding in nine cities in Metro Manila on Saturday and triggered a lahar warning around Pinatubo and Taal volcanoes.
The southwest monsoon or “habagat” is expected to bring heavy rainfall of up to 200 millimeters to parts of Luzon through Tuesday, Sept. 1, with Metro Manila among areas facing the heaviest rains through Sunday afternoon, the state weather bureau said Saturday.
La Mesa overflows
La Mesa Dam was overflowing as its water level reached 80.25 meters as of 5 p.m. Saturday, above its 80.15-meter spill level, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (Pagasa) reported.
Pagasa said excess floodwaters from the dam would flow directly into the Tullahan River, affecting low-lying areas in Quezon City, Caloocan City, Valenzuela City, Malabon City and Navotas City.
Among the areas identified by Pagasa were Fairview, Forest Hills Subdivision, Quirino Highway, Sta. Quiteria and San Bartolome in Quezon City, and North Expressway and La Huerta Subdivision in Valenzuela City.
Pagasa also warned that continuous rainfall over the watershed could further raise the river's water level.
As of 5:06 p.m., the Metropolitan Manila Development Authority (MMDA) reported flooding in Quezon City, Manila, Marikina, Mandaluyong, Pasay, Parañaque, Las Piñas, Malabon and Valenzuela.
Floodwaters in several areas reached gutter- to waist-deep levels, with some roads becoming impassable to light vehicles and, in deeper areas, all types of vehicles.
In Quezon City, water along Araneta-Talayan reached waist depth, or about 37 inches, and was not passable to all types of vehicles. G. Araneta Sr. Avenue was also reported waist-deep and impassable to all vehicles.
Flooding along E. Rodriguez Avenue in Quezon City reached knee depth, or about 19 inches, and was not passable to light vehicles. Parts of Araneta Avenue near Maria Clara Street were also reported impassable to light or all vehicles due to flooding.
In Valenzuela City, flooding along MacArthur Highway near Pio Valenzuela Street reached knee depth and was not passable to light vehicles.
The A. Fernando northbound and southbound portions of MacArthur Highway were also reported knee-deep, or about 19 inches, and impassable to light vehicles.
In Las Piñas City, Zapote Junction was knee-deep and not passable to light vehicles.
In Manila, flooding was reported along several major roads, including Rizal Avenue near Rapa, where water reached half-knee depth, or about 16 inches, making the area impassable to light vehicles.
Roxas Boulevard northbound from Pedro Gil to Kalaw was reported half-knee deep, or about 10 inches, but remained passable to all types of vehicles.
In Malabon City, flooding along Rizal Avenue Extension reached half-knee depth, or about 10 inches, but remained passable to all types of vehicles.
Flooding was also reported in Mandaluyong, Parañaque, Marikina and Pasay, although the affected roads remained passable to all types of vehicles.
Thirteen local government units (LGUs) in Metro Manila suspended classes in public and private schools on Saturday, Aug. 29, due to rainfall brought by the southwest monsoon.
The affected cities are Caloocan, Valenzuela, Manila, Navotas, Marikina, Malabon, Las Piñas, Mandaluyong, Taguig, Pasay, Muntinlupa, San Juan and Parañaque.
Lahar warning
The Philippine Institute of Volcanology and Seismology (Phivolcs) on Saturday warned that heavy rains could generate volcanic sediment flows or lahars, muddy streamflows or muddy run-off in rivers and drainage areas.
“Prolonged and intense rainfall may generate non-eruption lahars on major rivers draining western Pinatubo Volcano, where significant deposits of the 1991 pyroclastic density currents (PDCs) remain on the watershed,” it said.
Phivolcs said Pinatubo lahar flows are likely to be channel-confined and occur on the upper to middle reaches of the Sto. Tomas-Marella and Bucao River systems but may transition to muddy streamflows and floods on the lower reaches and affect adjacent communities of San Marcelino, San Narciso, San Felipe, and Botolan in Zambales province.
Muddy streamflows may also be generated along the O’Donnell and Pasig-Potrero River systems draining the Pinatubo edifice to the north and southeast, respectively, and affect downstream communities in Tarlac and Pampanga provinces.
“Prolonged and heavy rainfall may also generate muddy streamflow, muddy runoff and even volcanic debris flows around Taal Volcano, particularly on the slopes west and north of Taal Lake,” Phivolcs said.
It said old and loose volcanic deposits, already saturated from previous rains, may be remobilized in streams, roads and across the lakeward slopes.
In particular, muddy and debris flows can recur in previously affected communities of Agoncillo, Laurel and Talisay in Batangas province.
Phivolcs advised communities and local government units of the identified areas to continually monitor storm conditions and take preemptive response measures for their safety.
More rain expected
In its 5 p.m. weather update, Pagasa forecast 100 to 200 millimeters of rainfall from Saturday to Sunday afternoon over Ilocos Sur, Pangasinan, La Union, Benguet, Bataan, Zambales, Tarlac, Pampanga, Bulacan, Metro Manila, Rizal and Cavite.
In Pampanga, Gov. Lilia Pineda ordered the forced evacuation of residents in high-risk areas as monsoon rains continue to pummel the province since Friday.
At least 3,400 families, or 12,394 individuals, are now in 203 evacuation centers across Pampanga.
On Friday, a swollen river in Lubao, Pampanga breached the embankment and swallowed several residential houses along the riverbank.
Another 50 to 100 millimeters is expected over Ilocos Norte, Abra, Apayao, Kalinga, Ifugao, Mountain Province, Nueva Vizcaya, Nueva Ecija, Laguna, Batangas, Occidental Mindoro and Oriental Mindoro during the same period.
From Sunday afternoon to Monday afternoon, Pagasa forecast 100 to 200 millimeters over Ilocos Norte, Ilocos Sur, La Union, Pangasinan, Abra, Benguet, Zambales and Bataan.
Areas expected to receive 50 to 100 millimeters during the period include Apayao, Kalinga, Ifugao, Mountain Province, Nueva Vizcaya, Tarlac, Nueva Ecija, Pampanga, Bulacan, Metro Manila, Rizal, Cavite, Batangas and Occidental Mindoro.
From Monday afternoon to Tuesday afternoon, 100 to 200 millimeters of rainfall is forecast over Ilocos Norte, Ilocos Sur, La Union, Pangasinan, Abra, Benguet and Zambales.
Pagasa placed Batanes, Apayao, Kalinga, Ifugao, Mountain Province, Nueva Vizcaya, Tarlac, Nueva Ecija, Bataan, Pampanga, Bulacan, Metro Manila, Rizal and Cavite in the 50-to-100-millimeter rainfall outlook for the same period.
The weather bureau warned that rainfall could be higher in mountainous and elevated areas.
It also cautioned that the effects of the expected rainfall could be worsened in areas that have already received significant rain in previous days.
Death toll rises
At least 32 people have died, 19 were injured and three remain missing due to the combined effects of the enhanced southwest monsoon and tropical cyclones Luis, Maymay and Neneng, which have already moved away from the country, the National Disaster Risk Reduction and Management Council (NDRRMC) reported on Saturday.
The latest NDRRMC data as of 7 a.m. Aug. 29 showed that Benguet recorded the highest number of fatalities at 15, all caused by landslides.
Baguio City accounted for 10 deaths, while La Trinidad recorded two and Atok three.
Rizal recorded four deaths, including two from a rockslide in Rodriguez, one from a fallen tree in Antipolo and one from drowning in Binangonan.
Batangas also recorded four deaths, with fatalities reported in Batangas City, Lipa, Santa Teresita and Mabini due to drowning, electrocution and landslide.
Other deaths were recorded in La Union (one), Quezon (one), Oriental Mindoro (one), Occidental Mindoro (two), Negros Occidental (one), and Caloocan City (two).
In San Marcelino, Zambales, the bodies of the two children who drowned after their motorboat capsized in Lake Mapanuepe on Thursday have been recovered on Saturday morning. One more person from the capsized boat is still missing, a pregnant woman.
Nineteen people were also reported injured. Benguet accounted for 12 of the injured, followed by Abra and Quezon City with two each, and Ilocos Sur, Rizal and Cavite with one each.
The injuries were caused by landslides, a fallen tree, strong currents and a vehicular accident.
The enhanced southwest monsoon and the earlier tropical cyclones have affected about 2.3 million families or 8 million people in the Ilocos Region, Cagayan Valley, Central Luzon, Bicol Region, Western Visayas, Zamboanga Peninsula, Calabarzon, Cordillera Administrative Region, National Capital Region and Mimaropa.
The NDRRMC said 297 evacuation centers have been established, sheltering about 7,500 families or 25,800 people.
About 2,900 houses have been damaged, including 2,600 partially damaged and 349 destroyed.
Infrastructure damage has reached P6.11 billion, while agricultural losses were estimated at P2.32 billion.
Government agencies have provided P1.65 billion worth of assistance to affected communities.
A total of 117 local government units have declared a state of calamity.
Most recently, Lingayen, the capital town of Pangasinan, was placed under a state of calamity as it continues to reel from heavy rains, flooding and other hazardous conditions brought by the southwest monsoon, or habagat.
These include Dagupan City; four municipalities in Pangasinan; 14 areas provincewide in Benguet; 12 in Bataan; 24 in Bulacan; 21 in Pampanga; 13 in Zambales; Rodriguez in Rizal; 23 areas provincewide in Cavite; and Nasugbu in Batangas.
In Occidental Mindoro, the declarations cover Sablayan, Paluan and Abra de Ilog.
Red alert
The Department of Social Welfare and Development (DSWD) said it is now on "Red Alert" status as it monitors the prolonged effects of the southwest monsoon in parts of Luzon and Visayas.
The alert status was heightened following the NDRRMC decision to raise the national alert status from Blue to Red effective 5 p.m. Friday due to recent weather systems affecting the country.
DSWD Assistant Secretary Irene Dumlao of the Disaster Response Management Group assured the public that the department continues to prepare for the possible effects of prolonged rains and flooding.
"We remain prepared, as we know that the effects of the southwest monsoon continue to persist in parts of Luzon and the Visayas. Our field offices are on heightened alert and our relief resources are ready so we can quickly address the needs of our countrymen if necessary," Dumlao, the DSWD spokesperson, said Saturday.
The Philippine Red Cross (PRC), meanwhile, has stepped up its humanitarian response as nearly 586,000 people have been affected by the combined effects of the enhanced southwest monsoon and tropical cyclones Luis and Maymay, citing figures from the NDRRMC.
In an emergency appeal issued Saturday, the PRC said 585,000 individuals, or 170,593 families, were affected across nine regions, 33 provinces, 225 cities and municipalities and 1,362 barangay (villages).
More than 32,000 people remain displaced, with many staying in evacuation centers or with relatives, while 4,866 individuals were preemptively evacuated, according to Red Cross.
The PRC said that it has been providing humanitarian assistance in affected communities, including evacuation support, relief distribution, welfare services and emergency response operations.
“Our Red Cross chapters and emergency rescue units are actively responding on the ground—rescuing stranded residents and even pets while delivering emergency food supplies to communities affected by rising floodwaters,” PRC Chairman and CEO Richard J. Gordon said.
The humanitarian organization said its teams and emergency rescue units continue to assist communities affected by flooding and other impacts of the weather disturbances. WITH PNA, BENJAMIN VERGARA, JANICE HIDALGO, ARNEL SAN PEDRO, MAHATMA RANDY DATU
