Nona and Onyok (2015) Flood and Debris Flows in Nueva Ecija, Pampanga and Bulacan

12 – 18 December 2015


Typhoon Nona (international name, Melor) and Tropical Depression Onyok were severe weather events that entered the Philippines between 12 and 18 December 2015. Nona entered the Philippine Area of Responsibility (PAR) as a Tropical Storm on 12 December 2015, traversed the central region of the country affecting many regions in the country including those near Metro Manila and weakened into a Low Pressure Area (LPA) by early December 17. Onyok overlapped with the typhoon with its entry late in December 16, bringing moderate to heavy rains in major parts of Mindanao until it dissipated into a Low Pressure Area on December 18 above the eastern provinces of Mindanao. Typhoon Nona caused 42 deaths due to flooding with some landslide incidents and more than 6.4 billion pesos in damages spread out across Region II, IV-A, IV-B, V, VII, and NCR. Tropical Depression Onyok, on the other hand, destroyed 8 houses in the CARAGA Region, caused more than 1 billion pesos in infrastructure damage in Davao Oriental but did not inflict any casualties (NDRRMC, 2015).

Very strong rainfall in the mountainous areas of Aurora and Sierra Madre on 16 December 2015, created massive floods and debris flows in Gabaldon, Laur and Dingalan in Nueva Ecija (Usman, 2015). Residents describe this event during Nona as worse than the debris flows of Lando. Landslide incidents in Nueva Ecija and Quezon were reported along with 332 flooded areas across Regions I, III, IV-B, V, and VIII. Runoff water from Nueva Ecija caused floods in Calumpit and Hagonoy Bulacan, La Paz Tarlac and Candaba Pampanga for weeks (GMA News, 2015).

Cabanatuan City inundated due to floods from Typhoon Nona. (Photo courtesy of Federico Cruz and Manila Bulletin)

Cabanatuan City inundated due to floods from Typhoon Nona. (Photo courtesy of Federico Cruz and Manila Bulletin)

President Benigno S. Aquino III declared a state of national calamity on 18 December 2015 due to the typhoon’s massive impact in Luzon and Visayas. The proclamation cited the widespread destruction, substantial damage, and deaths in several areas, including the provinces of Albay, Northern Samar, Oriental Mindoro, Romblon and Sorsogon (Alvarez, 2015). Typhoon Nona also caused devastation in the provinces of Aurora, Nueva Ecija, Pampanga, and Bulacan.

With downpour from Typhoon “Nona” washing away roads and rice fields, residents in Barangay Rajal Sur in Santa Rosa, Nueva Ecija province, rely on carabao power to get them to their destinations.  (Photo courtesy of Niño Jesus Orbeta and Philippine Daily Inquirer)

With downpour from Typhoon “Nona” washing away roads and rice fields, residents in Barangay Rajal Sur in Santa Rosa, Nueva Ecija province, rely on carabao power to get them to their destinations. (Photo courtesy of Niño Jesus Orbeta and Philippine Daily Inquirer)

In preparation for the effects caused by heavy rainfall from Tropical Depression Onyok, Preemptive evacuations were carried out in vulnerable areas of Davao Oriental, Compostela and New Bataan in Compostela Valley. Landslides were reported in Compostela Valley but caused no casualties or injuries according to the PDRRMC. In Davao Oriental, many families were evacuated after Kasaulman River, Manay River and Mahan-ub River swelled from heavy rains but were able to return home in the morning of 19 December 2015 (Lopez, 2015).

Screenshot of Dr. Lagmay's Twitter post on the rainfall contour during Typhoon Nona and Onyok (photo courtesy of GMA News)

Screenshot of Dr. Lagmay’s Twitter post on the rainfall contour during Typhoon Nona and Onyok (photo courtesy of GMA News)

Twitter post of Dr. Lagmay warning of possible floods in Central Luzon. (Photo courtesy of GMA News)

Twitter post of Dr. Lagmay warning of possible floods in Central Luzon. (Photo courtesy of GMA News)


Alvarez, Kathrina C. (2015). PNoy declares state of national calamity due to Nona. GMA News Online.
http://www.gmanetwork.com/news/story/548396/news/nation/pnoy-declares-state-of-national-calamity-due-to-nona#sthash.QIBwSulQ.dpuf

De Vera, E., Crisologo, S., and Usman, E. (2015). Widespread flooding feared: Residents in low-lying areas in Bulacan, Pampanga warned. Manila Bulletin.
http://www.mb.com.ph/widespread-flooding-feared/

GMA News. (2015). Floods hound 3 Central Luzon provinces days after typhoon. GMA News Online. http://www.gmanetwork.com/news/story/548338/news/regions/floods-hound-3-central-luzon-provinces-days-after-typhoon#sthash.sxYr4QdM.dpuf

GMA News. (2015). Typhoon Nona turns Pinamalayan town in Oriental Mindoro into wasteland. GMA News Online.
http://www.gmanetwork.com/news/story/548350/news/regions/typhoon-nona-turns-pinamalayan-town-in-oriental-mindoro-into-wasteland#sthash.d0XCe1OL.dpuf

Inquirer.net. (2015). Floods swamp Central Luzon; dams full. Philippine Daily Inquirer.
http://newsinfo.inquirer.net/748625/floods-swamp-central-luzon-dams-full

Lopez, Alexander D. (2015). LPA ‘Onyok’ triggers floods, landslides in Davao region. Manila Bulletin.
http://www.mb.com.ph/lpa-onyok-triggers-floods-landslides-in-davao-region/#7BI1XxrWYSot0lo1.99

NDRRMC. (2015). Sitrep No. 19 re: Preparedness Measures and Effects of Typhoon “NONA” (I.N. MELOR).
http://www.ndrrmc.gov.ph/attachments/article/2663/ASitRep_No_19_re_Preparedness_Measures_and_Effects_of_Typhoon_NONA_24DEC2015_0600H.pdf

NDRRMC. (2015). Sitrep No. 08 re: Tropical Depression “ONYOK”.
http://www.ndrrmc.gov.ph/attachments/article/2665/Sitrep_No.08_re_Tropical_depression_ONYOK_22DECEMBER2015_0800H.pdf

Philippine Statistics Authority. (2012). 2010 Census of Population and Housing.
https://psa.gov.ph/sites/default/files/attachments/hsd/pressrelease/Central%20Luzon.pdf

Usman, Edd K. (2015). DOST warns of flood as ‘Nona’ rainwater level rivals ‘Lando’: NOAH’s Lagmay urges vigilance even if ‘Nona’ is leaving PAR. Manila Bulletin.
http://www.mb.com.ph/dost-warns-of-flood-as-nona-rainwater-level-rivals-lando/

Virola, M. (2015). Oriental Mindoro under state of calamity. Philippine Daily Inquirer.
http://newsinfo.inquirer.net/748265/oriental-mindoro-under-state-of-calamity

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