..Communities in Quezon City, Valenzuela and Malabon were alerted yesterday to the possible overflow of the La Mesa Dam in Quezon City.
Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) weather specialist Oyie Pagulayan said the water level in La Mesa was at 79.76 meters as of 1 p.m. on Saturday, 0.3 meters below the normal level of 80.15 meters.
The warning was issued as tropical storm Ambo, which is expected to bring heavy rainfall, approached Northern Luzon.
Hundreds of travelers were stranded in Bicol and the Visayas and flights were cancelled as the storm neared.
"If we consider the forecast rainfall of the (PAGASA) Forecasting Division, we may likely reach the dam's overflowing level," Pagulayan said noting the forecast rainfall at 15-25 mm per hour within the diameter of Ambo, is considered heavy rains.
Reports cited that authorities of the La Mesa already advised the concerned local government units (LGUs) to warn residents that will be directly affected by the flow of excess water to be on alert for possible flash floods.
Communities that may likely be affected by flooding are Fairview, Forest Hills, Quirino Highway, Papri, Goodwill, Sta. Quiteria, and San Bartolome in Quezon City, Barangay Ligon along North Luzon Expressway in Valenzuela and Malabon.
Pagulayan also noted that one spillway gate of Magat Dam in Isabela was opened Friday night in anticipation of heavy rainfall.
As of yesterday afternoon, the level in Magat was 191.88 meters. The gate was opened one meter, releasing 228 cubic meters of water per second, she said.
The normal level of Magat is at 193 meters.
One gate of Binga Dam in Benguet was also partially opened to let out water.
"The dam's water level was 572.46 meters as of 1 p.m. Saturday," Pagulayan said.
She pointed out that the water released from Binga will cascade down to the San Roque Dam in Pangasinan, whose level is relatively low as of yesterday.
Undersecretary Benito Ramos, executive director of the National Disaster Risk Reduction and Management Council (NDRRMC), said the bulk of the stranded passengers, nearly 500 persons, were in Tabaco port, on their way to Catanduanes.
A later report from the Philippine Coast Guard put the number of stranded passengers at 920.
About 30 people in a fishing boat were reported to drifting in the middle of the sea off Catanduanes.
Raffy Alejandro, director of the Office of Civil Defense Bicol, said the report they received was that the boat ran out of gasoline. The passengers, on the other hand, are safe.
Alejandro said a rescue team cannot head out to sea because it was too dangerous.
Yesterday morning, Ambo was spotted off Aurora heading towards Northern Luzon at 13 kilometers per hour. The storm was packing 75 kph winds and gusts of up to 90 kph.
As of Saturday afternoon, storm signal 2 was raised over Calayan island and the Batanes group of islands . Signal No. 1 was hoisted over Northern Aurora Isabela, Cagayan and Babuyan island.
Ramos said police and military units were standing by for search, rescue and evacuation missions in areas most likely hit with flashflood and landslides.
Aldzar Aurelio said the eye of "Ambo" was estimated at 200 kilometers east-northeast of Casiguran, Aurora at 10 a.m. on Saturday.
The storm slightly intensified with maximum sustained winds up to 85 kilometers per hour (kph) and gustiness of up to 100 kph.
"If it maintains its speed and direction, Ambo is expected to move out of the Philippine area of responsibility by Tuesday," Aurelio said.
Ambo is expected to be at 240 km northeast of Aparri, Cagayan by this morning. It will be at 350 km northeast of Basco, Batanes by tomorrow morning.
Inclement weather brought about by tropical storm Ambo caused the cancellation of 32 domestic flights yesterday morning.
According to reports reaching the Ninoy Aquino International Airport's Media Affairs Division, flag carrier Philippine Airlines cancelled flights PR277 and PR278 which is a turnaround flight service between Manila and Legaspi City.
Cebu Pacific also cancelled turnaround flight services between Manila and Legaspi City, Manila and Naga City, Manila and Busuanga, and most of its Manila and Caticlan flights.
Air Philippines cancelled flight 2P040 which is the return segment from Caticlan to Manila.
The management from the three airline companies said all affected passengers will be accommodated on the succeeding flights as soon as the weather in the area improves and flight services resume. (With reports from Chito Chavez, Raymund Antonio and Anjo Perez)