On November 1, 2020, the Philippines was hit with the world’s strongest storm this year called Typhoon Goni, locally known as Bagyong Rolly.  The typhoon brought catastrophic winds and intense rains in the southern portion of Luzon, including CALABARZON. It was categorized as a super typhoon even before it has made its landfall. Its strength of 225 kilometers per hour (kph) sustained winds and gustiness of up to 310 kph was comparable to that of Typhoon Yolanda back in 2013. The Department of Science and Technology – Philippine Atmospheric, Geophysical and Astronomical Services Administration (DOST – PAGASA) reported that Typhoon Rolly has made its third landfall in San Narciso, Quezon at noon on November 1, 2020, and in Lobo, Batangas at 5:30 PM on the same day. This Office made its Operations Center into an Emergency Operation Center (EOC) that day to thoroughly keep track of the effects of the typhoon in CALABARZON.

To keep everyone in the region posted, this Office disseminated barangay listings of flood and landslide susceptibility ratings all over CALABARZON including member agencies such as the Department of Environment and Natural Resources Regional Office No. IV-A (DENR-IV A), Provincial Disaster Risk Reduction and Management Offices (PDRRMOs), and City/Municipality Disaster Risk Reduction and Management Offices (C/MDRRMOs). All provinces experienced light to heavy flooding, and some had occurrences of landslides as well.

An overflow of the Laguna de Bay was reported during the onset of the Typhoon. The water level rose about six feet higher than its normal water level, flooding municipalities in the Laguna Province surrounding the lake as a result. It also caused light flooding in Angono, Rizal.

Some barangays in Calamba City that were not next to the lake still experienced below-knee deep flooding during the landfall. There was also a reported landslide in Barangay Matalinting, Sta. Maria the next day. The landslide area was declared to be passable soon after.

In the Province of Batangas, Batangas City experienced a landslide along the Batangas-Lobo Road and Lobo along its national road in Brgy. Malapad na Parang and Brgy. San Miguel. Flooding incidents were reported in Lobo, Lian, Lipa City, Malvar, San Jose, and Taysan. In addition, an existing fissure in Brgy. Mataas na Bayan, Lemery was reported to have widened due to erosion caused by heavy rainfall.

Quezon Province was the hardest hit amongst the provinces in CALABARZON. Tropical cyclone wind signal no. 4 was declared in some portions of the said province. Cases of heavy floods were reported in San Andres, Tagkawayan, Catanauan, Polilio, Real, Macalelon, Sampaloc, San Francisco, Mauban, San Narciso, and Mulanay. Brgy. Madulao, Catanauan even had chest-deep floods due to the typhoon. In San Narciso, the flood was deep enough to submerge entire houses.

In some areas of Quezon, the winds were strong enough to topple trees and structures, blow up tin roofs and even destroy houses. These fallen objects caused impassable roads such as one of that in Brgy. Butanyog, Mulanay, Quezon.

Assessments shall be conducted by this Office in areas in CALABARZON with flooding and landslides. One has already been done in Lemery, Batangas. Results from the said assessment shall be shown in a detailed 1:10,000 scale Rain-Induced Landslide and Flooding Susceptibility Map of the concerned municipalities and in the Landslide and Flooding matrix of this Office.

A fissure in Brgy. Mataas na Bayan, Lemery, Batangas.
Source: Christian Jake Abalos
 

Spillway overflow in Brgy. Quilo, Ibaan.
Source: Batangas PDRRMO.

 

Chest-deep flood in Barangay Madulao, Catanauan, Quezon.

 

Knee-deep flood in Catanauan, Quezon.


By : Engr. Patrizia S. Benedicto                   |        5 November 2020