More than 3,682 individuals, comprising over 1,200 families, have been forced to evacuate as Tropical Depression Luis and an enhanced southwest monsoon triggered flooding across several areas of the Philippines, the Office of Civil Defense (OCD) reported on Tuesday.

According to OCD Deputy Spokesperson Diego Agustin Mariano, who briefed reporters via Viber citing data as of 6:00 a.m., the evacuees are part of a broader population of 9,381 affected persons — or approximately 7,701 families — impacted by the two weather systems.

"Reported affected population are from Regions II, III, V, and IX," Mr. Mariano said.

The southwest monsoon, locally known as "habagat," is a seasonal weather pattern that regularly brings heavy rainfall to the Philippines, particularly during the months of June through September. When enhanced by tropical cyclones such as Luis, the monsoon can produce widespread flooding and landslides across large swathes of the archipelago. Even relatively weak systems like tropical depressions, which carry lower wind speeds than typhoons, can dramatically amplify monsoon rainfall and overwhelm drainage infrastructure, making flooding — not wind damage — the primary hazard during such combined events.

The OCD confirmed that more than P1.2 million worth of assistance has already been distributed to affected individuals. As of the latest update, the agency has not reported any casualties or property damage directly attributed to Tropical Depression Luis and the enhanced monsoon.

In addition to the evacuations, the OCD documented 18 flooded areas across Regions I, IX, and the Bangsamoro Autonomous Region in Muslim Mindanao (BARMM). The agency has further identified 398 barangays in Region II, the Cordillera Administrative Region (CAR), and the MIMAROPA region as being susceptible to flooding and rain-induced landslides.

The Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) maintained Heavy Rainfall Warnings for several provinces in Luzon, including Zambales, Bataan, Benguet, La Union, and Pangasinan. Intense rainfall is expected to persist in these areas until Wednesday afternoon.

The OCD, which operates under the Department of National Defense, serves as the coordinating body for disaster response and civil protection in the Philippines, a country that experiences an average of approximately 20 tropical cyclones annually and consistently ranks among the most disaster-prone nations globally. The agency's pre-emptive evacuation approach reflects disaster management protocols refined in the wake of past major storms, particularly Typhoon Haiyan (Yolanda) in 2013, which prompted significant reforms in the country's early warning and mass evacuation systems.

— Edg Adrian A. Eva