- The year 2020 recorded one super typhoon, six typhoons, three severe tropical storms, six tropical storms, and six tropical depressions, surpassing the annual average of 19 to 20 tropical cyclones that visit the Philippines each year.
- The first cyclone of 2020, typhoon "Ambo" (Vongfong), was also one of the most remarkable cyclones of the year after leaving at least P1 billion worth of damages to infrastructure and agriculture.
- With the onset of a moderate-to-strong La Niña in October, the country recorded eight cyclones in a row, seven of which made landfall over Luzon including one that developed into a super typhoon.
- The strongest cyclone to hit the archipelago in 2020 was Rolly which reached the highest tropical cyclone classification when it made landfall over Bicol region. The super typhoon carried maximum sustained winds of 235 kph and gusts of up to 265 kph when it hit Catanduanes in the early morning of Nov. 1.
- Towards mid-November, typhoon Ulysses came and caused much destruction. Tens of thousands of homes in low-lying communities in Metro Manila and Cagayan Valley were submerged by floods, prompting residents to scramble onto rooftops awaiting rescue.
- For incurring at least P1 billion worth of damages, typhoons Ambo, Quinta, Rolly, and Ulysses are expected to be retired from the PAGASA’s list of tropical cyclone names for the coming years.
- In November, 40 percent of the country received above normal rainfall, mostly in Luzon; while 49 percent had below to near normal rainfall, particularly in Visayas and Mindanao; while the remaining 11 percent had below normal rainfall.
What initially appeared to be an uneventful tropical cyclone season, later turned out to be one of the most active in the past decade, recording 22 tropical cyclones for the whole year—eight of which occurred one after another in the last quarter of 2020.
With the onset of a moderate-to-strong La Niña in October, the country recorded eight cyclones in a row, seven of which made landfall over Luzon including one that developed into a super typhoon.
Except for tropical storm "Nika" (Nangka), the seven cyclones—tropical depression "Ofel," typhoon "Pepito" (Saudel), typhoon "Quinta" (Molave), super typhoon "Rolly" (Goni), severe tropical storm "Siony" (Atsani), tropical storm "Tonyo" (Etau), and typhoon "Ulysses" (Vamco) all traversed Luzon.
The year 2020 in total recorded one super typhoon, six typhoons, three severe tropical storms, six tropical storms, and six tropical depressions, surpassing the annual average of 19 to 20 tropical cyclones that visit the Philippines each year.
It was not until May and at the height of the pandemic, however, that the first cyclone of the year had developed.
Named typhoon "Ambo" (Vongfong), the first cyclone of 2020 was also one of the most remarkable cyclones of the year after leaving at least P1 billion worth of damages to infrastructure and agriculture.
After Ambo in May and tropical storm "Butchoy" (Nuri) in June, the 11 succeeding tropical cyclones from July to September--tropical depression "Carina," severe tropical storm "Dindo" (Hagupit), tropical storm "Enteng" (Jangmi), tropical depression "Ferdie," tropical depression "Gener," tropical depression "Helen," severe tropical storm "Igme" (Bavi), typhoon "Julian" (Maysak), typhoon "Kristine" (Haishen), tropical storm "Leon" (Noul), and tropical storm "Marce" (Dolphin)—barely made landfall in the country.
Calm before the storm
The relatively quiet tropical cyclone season in the first three quarters of the year however turned out to be the calm before the storm, literally.
By October, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) had announced the onset of a moderate-to-strong La Niña, which is usually associated with above normal rainfall conditions across most areas of the country during the last quarter of the year and early months of the following year.
In this period, the country saw the strongest cyclone to hit the archipelago in 2020—Rolly—which reached the highest tropical cyclone classification when it made landfall over Bicol region.
(Photo by Charism SAYAT / AFP / MANILA BULLETIN)
Rolly went on to hit Calabarzon a few more times as a typhoon, leaving a massive trail of destruction along its path.
Torrential rains from Rolly triggered volcanic ash and debris to cascade from Mayon Volcano's slopes, burying villages at the foot of the volcano.
Rolly's vicious winds likewise caused major damage to PAGASA's Doppler radar—one of the country's first lines of defense against severe weather—that was located in Bato, Catanduanes.
The super typhoon carried maximum sustained winds of 235 kilometers per hour (kph) and gusts of up to 265 kph when it hit Catanduanes in the early morning of Nov. 1. Its strong winds proved just too much for the radar that was supposed to withstand up to 250 kph of winds.
It reached P17 billion in damages and some 25 fatalities in its aftermath.
More destruction
Due to the catastrophic impact of Rolly, compounded by subsequent tropical cyclones and other rain-bearing weather systems, destruction from the passage of typhoon Ulysses towards mid-November became more evident.
Tens of thousands of homes in low-lying communities in Metro Manila and Cagayan Valley were submerged by floods, prompting residents to scramble onto rooftops awaiting rescue.
The severe flooding in Metro Manila and nearby provinces in Central Luzon and Calabarzon had brought back the grim memory of tropical storm "Ondoy" (Ketsana) in 2009.
During the onslaught of Ulysses, Marikina River‘s water level breached its 21.5-meter record at the time of Ondoy.
Data from PAGASA however showed that Ulysses dumped lesser rain than Ondoy during its onslaught in Metro Manila, although a large volume of rainfall on upstream rivers and previous cyclones had influenced the swelling of waterways that flooded the metropolis.
Cagayan Valley widespread flooding
It is also during this period that Cagayan Valley experienced its "worst flooding" in decades, local officials reported.
Aside from being a catch basin of rainwater from upstream Cagayan Valley and Cordillera Administrative Region, the opening of floodgates of Magat Dam was also seen to have contributed to the widespread flooding in Cagayan province.
Authorities also noted that the already saturated soil from previous tropical cyclones before Ulysses and other rain-bearing weather systems further aggravated the situation.
The National Irrigation Administration (NIA), the operator of Magat Dam, however reiterated that water discharge protocols had been followed. It further explained that the Magat river basin is only one of the 20 river systems within the Cagayan river basin, pointing out that the water released from Magat Dam "is not the main contributor to the flooding."
NIA also cited studies showing that Magat Dam contributes only 15 percent of the river basin’s total water storage capacity and 21 percent if the considered control point will be in Buntun Bridge in Tuguegarao City.
The discussions on Magat Dam's discharge protocols have prompted authorities to review the document, which was last updated in 2006.
Authorities, led by NIA, have yet to release a new set of protocols for the opening of Magat Dam's floodgates.
For incurring at least P1 billion worth of damages, typhoons Ambo, Quinta, Rolly, and Ulysses are expected to be retired from the PAGASA’s list of tropical cyclone names for the coming years.
La Niña to persist until early 2021
PAGASA said 92 percent of the country received above normal rainfall in October, with "many areas (that) had received more than 200 percent of the normal rainfall."
The State weather bureau had forecast two or three tropical cyclones in October, but then five tropical cyclones were recorded at the end of the month.
Comparing the frequency of tropical cyclones during the month of October from 1950 to 2020, PAGASA noted that many tropical cyclones had formed in October during La Niña years.
In November, 40 percent of the country received above normal rainfall, mostly in Luzon; while 49 percent had below to near normal rainfall, particularly in Visayas and Mindanao; while the remaining 11 percent had below normal rainfall.
PAGASA pointed out that a La Niña event increases the potential of having extreme rainfall events caused by rain-bearing weather systems, such as northeast monsoon or "amihan," tail-end of cold front, intertropical convergence zone, low pressure areas, and tropical cyclones.
(Photo by Ted ALJIBE / AFP)
The last cyclone to have formed inside the country this year was tropical depression "Vicky" in December.
Ana Liza Solis, chief of the climate monitoring and prediction section of PAGASA, said there is a 95 percent chance that the current La Niña will continue through January-February-March 2021 period.
"There is still a high likelihood of above normal rainfall conditions that could lead to potential adverse impacts, such as heavy rainfall, floods, landslides over highly vulnerable areas," she said.
"Mostly during this time of year, the highly vulnerable areas are those in the eastern section of Visayas and Mindanao," Solis added.
Zero or one tropical cyclone each in January, February, and March is forecast to form or enter the Philippine area of responsibility.
PAGASA said rainfall will be generally above normal in Metro Manila, Southern Luzon, Bicol region, Visayas, and Mindanao, while the rest of Luzon will likely to receive below to near normal rainfall conditions in January.
By February, mostly near to above normal rainfall conditions are likely over the southern parts of Luzon, Visayas, and Mindanao, while the rest of Luzon will likely experience below to near normal rainfall conditions.
The weather bureau noted that by March, rainfall will be generally near to above normal over Bicol region and most parts of Visayas and Mindanao, while the rest of Luzon will likely to receive below to near normal rainfall conditions.