Quezon City reeled from what officials described as a “phenomenal” downpour on Saturday, with rainfall briefly surpassing levels recorded during tropical storm “Ondoy” in 2009 and overwhelming parts of the city’s drainage system.

The Quezon City Disaster Risk Reduction and Management Office (QC-DRRMO) said the city recorded a peak of 121 millimeters of rain in just one hour and a 24-hour accumulation of 141 millimeters on Saturday.

Philippine Atmospheric, Geophysical, and Astronomical Services Administration (PAGASA) noted that 116 millimeters fell between 2 p.m. and 5 p.m. alone, describing it as “intense to torrential” — well above the 50 mm threshold that usually triggers localized flooding.

“The rainfall was truly phenomenal. With its sheer volume and speed, the drainage system couldn’t handle it, causing flooding even in areas that rarely get submerged,” QC-DRRMO spokesperson Peachy de Leon said, adding that the San Juan River reached Alert Level 3 and spilled into nearby barangays.

Streets turned into rivers

Floodwaters rose swiftly in key areas: Mother Ignacia Avenue, Katipunan, EDSA-North Avenue, Maginhawa, Araneta Avenue, Commonwealth, and Mindanao Avenue. In under an hour, parts of the Elliptical Road and South Triangle were submerged, forcing commuters to walk through waist-deep water.

Traffic gridlock stranded thousands of motorists, with many vehicles reported stalled in low-lying underpasses. Several bus passengers were forced to climb onto vehicle roofs when floodwaters rushed into the Timog and Kamuning areas.

By evening, the Metropolitan Manila Development Authority (MMDA) said eight pumping stations in QC and nearby cities were operating at full capacity, while barangay responders deployed rubber boats for rescues in Del Monte, Bagong Silangan, Dona Imelda, Roxas, Tatalon, and Apolonio Samson.

At least 200 families were evacuated to barangay gyms and public schools, while several weekend markets in Commonwealth and Project 6 closed early, leaving vendors with spoiled goods. Power interruptions were also reported in pockets of District 3.

Drainage, garbage, and urban sprawl

Officials admitted the city’s drainage system had limits, though they credited mitigation programs for preventing a catastrophe on the scale of Ondoy.

The “Tanggal Bara, Iwas Baha” program, which mobilizes all 142 barangays to declog esteros and street inlets, has reportedly cleared over 1,200 truckloads of garbage since January. Still, tons of plastic waste carried by floodwaters clogged canals in Tatalon and Roxas, worsening the overflow.

“Rain isn’t the only problem. Garbage remains the main culprit. No matter how big the drainage system is, if it’s clogged with plastics and appliances, it’s useless,” de Leon said.

In San Antonio, Quezon City, Barangay Captain Daniel Berroya took to social media on Saturday to share their community’s ordeal after hours of heavy rain.

“Did the water really flood? Why did the garbage flood even more? I wonder why?” Berroya wrote in Filipino, posting photos and videos of streets blanketed by debris washed in by the storm.

Barangay Public Safety Officer Shiela Samoraga told DAILY TRIBUNE that such scenes are not new to them. “Our barangay is a catchment area,” she explained. “Floodwaters bring in debris from other barangays through the San Juan River, and it all ends up here.”

Later that day, Berroya posted a follow-up update showing a street that had already been cleared.

“Nothing is impossible through communal unity,” he said in Filipino, expressing gratitude to the QC Environmental Team and the Department of Sanitation and Cleanup Works for their swift response.

"Ondoy" comparisons, climate warnings

Experts at the UP Resilience Institute noted that the city’s urban sprawl — with more paved surfaces, gated communities, and commercial complexes — reduced natural drainage and worsened runoff.

The flooding revived painful memories of Ondoy in 2009, which dumped more than 300 mm in just six hours and left entire districts underwater for days.

Scientists warned that extreme thunderstorms are becoming more frequent under climate change. PAGASA said localized thunderstorms — like Saturday’s — may now drop rainfall amounts equivalent to a month’s worth of normal August rain in just a few hours.

Call for long-term solutions

City officials renewed calls for a faster rollout of the ₱20-billion Drainage Master Plan, which includes larger drainage mains, catch basins, and inter-city flood control coordination with Manila, San Juan, and Caloocan.

QC Mayor Joy Belmonte vowed to bring up the incident with national agencies this week. “Our teams responded quickly and our systems worked to some extent, but this shows we need bigger, long-term solutions. It is not only Quezon City which was affected — the whole Metro Manila,” she said.