Intense: Typhoons getting fiercer

INTENSE: Typhoons getting fiercer

By Kristine Angeli Sabillo
INQUIRER.net

Tears fall from the eyes of Anelyn and Nalvin Abdulsali as they recall events from three years ago. “Pablo” was supposed to be just another storm.

At that time, the brother and sister were looking after boats moored in Cabugao Island, a picturesque feature in Boston town, Davao Oriental. The day before, their father had already asked for provisions and relief goods from the local government in preparation for the typhoon (international name Bopha), which was expected to make landfall farther north. Authorities had tried to convince him to stay in town with his relatives, but he insisted that he and his family seek shelter in the mountainous part of the island.

They were cooking rice, Anelyn says, when the typhoon’s strong winds hit land. Before they could run for higher ground, large waves pummelled the island and pulled them toward the water.

Their mother, who was carrying their baby brother, was able to run toward the mountains; that’s where they were eventually reunited. But by then, their father was already in the throes of an asthma attack. He was panting heavily as he rested beside a coconut tree.

Nalvin then recalls seeing something similar to a tornado come bearing in. The winds were so strong it uprooted the coconut tree, which fell on their father.

“Mother said, ‘Vin, your father is dead,” Nalvin tells INQUIRER.net as he sits crying by the shore, Cabugao Island just behind him. “We looked and saw that he was really dead.”

It has been three years since Pablo devastated the towns of Cateel, Banganga and Boston, in Davao Oriental, but its scars are still visible — in the hills emptied of coconut trees and in the faces of children like Anelyn and Nalvin.

BACKSTORY:
Typhoon ‘Pablo’ pounds Mindanao
Typhoon ‘Pablo’ death toll exceeds 1,000-mark
‘Pablo’ was deadliest catastrophe in the world in 2012

“To be honest, when I returned, I cried,” says Boston Mayor Rebecco Rosit, who recalled returning to town after the typhoon. “There were no more coconuts. There were no more trees.”

Pablo struck the eastern side of Mindanao with sustained winds of 280 kilometers per hour. At least 1,067 people were reported dead while 834 declared missing; strong winds obliterated houses and toppled trees.

It was unlike anything they had seen before, residents would say again and again.

READ:
Typhoon Pablo awes Davao residents
So that’s what a typhoon is like

More powerful

“Pablo” was supposed to be just another storm—except that it hit Mindanao, and that it was stronger than usual.

“The fact is already there, that the typhoons are getting stronger,” said Lucille Sering, just recently chair of the Climate Change Commission of the Philippines.

“There are several factors that create a typhoon. It’s like a dish, there are different ingredients. And in a typhoon, one of the ingredients is increase in temperature…So that’s where there’s a conversation on typhoons and climate change, because the increase in temperature [is] really making the typhoons stronger.”

A year before Pablo, the national weather bureau released a report on the impact of climate change in the Philippines. With the appropriate caveats, the Pagasa report notes “a very slight increase in the number of tropical cyclones with maximum sustained winds of greater than 150kph and above (typhoon category) being exhibited during El Nino years.”

Even earlier, in 2007, the Intergovernmental Panel on Climate Change, the international authority on the science of global warming, issued its Fourth Assessment Report with similar language.

“It is likely that future tropical cyclones (typhoons and hurricanes) will become more intense, with larger peak wind speeds and more heavy precipitation associated with ongoing increases of tropical sea surface temperatures.”

In the IPCC scale, “likely” means a probability of 67 to 90 percent.

More intense

The IPCC’s Fifth Assessment Report, released last year, reflects a more tempered look at the data, but nevertheless says the frequency of tropical cyclones will likely decrease or remain unchanged while more intense storms are expected in some areas.

Climage Change 2013 The Physical Science Basis

Professor Johnny Chan, director of the Guy Carpenter Asia-Pacific Climate Impact Centre, has argued that the primary effect of climate change on extreme weather is revealed in climate model projections that show an overall decrease in typhoon activity and increased intensity of up to 10 percent.

“In the area of the Philippines, the number of typhoons has been decreasing for the last 15 years. However, that does not mean that the threat has decreased,” Chan wrote. “Good examples would be Haiyan and the recent Koppu typhoons.”

Last year, Professor Jim Elsner of the Florida State University and Namyoung Kang, now deputy director of the National Typhoon Center in South Korea, found that there were 6.1 fewer tropical cyclones in the last 30 years, because of warmer oceans, but packed winds were stronger by at least three miles per hour. It was “a tradeoff between frequency and intensity,” Elsner told Science Daily.

But, for Sering, what is more important for countries like the Philippines is to already find ways to prepare for stronger typhoons or more extreme weather.

“What I care about is, ‘What can I do if my typhoon will be stronger than Yolanda? What can we do if our temperature is higher than what it is right now. Will it impact my food?’ And I think that’s where we’re looking at it right now. How to prepare for something that we feel will already happen,” she said.

Shifting tracks?

Before Pablo, Davao Oriental was known as a land that was relatively safe from strong typhoons. But that belief has now changed.

Dolores Valdesco, officer in charge of the Davao Oriental Environment and Natural Resources Office, said Pablo “jolted [them] to reality, that climate change is real.”

Valdesco said the provincial government used to promote Davao Oriental as a tourist destination that lies outside the “typhoon belt” of the Philippines, meaning it was safe from strong tropical cyclones.

“These are areas and routes not regularly taken by typhoons. Why did the typhoon track shift southward? Why were we affected? It is one indicator of climate change linked to extreme weather conditions,” she said in Filipino.

The IPCC notes that while studies and models project a poleward shift among tropical cyclones, there isn’t enough data yet to show a clear tend.

Thelma Cinco, head of the national weather bureau’s Impact Assessment and Applications Section, also noted that while there is a recent increase in the number of tropical cyclones affecting Mindanao, these can only be attributed to variability because of insufficient data.

However, she pointed out, “if you look at the recent years, typhoons hitting the north are decreasing and those hitting the south are increasing. They [residents in the south] are more vulnerable because they are not used to strong typhoons.”

Those in the north like the island of Batanes have long adjusted to extreme weather by constructing houses that are resilient to strong winds. Now, she said, towns not used to typhoons should also prepare for climate change.

“Adaptation. We must be ready for that,” Cinco said.

‘Explosive deepening’—
The science behind Yolanda

Around 4,500 kilometers east southeast of the Philippines, something big was forming.

It was Nov. 2, 2013. Hundreds of kilometers off the Micronesian island of Pohnpei, warm and moist air had started rising from the warm ocean surface, creating a low pressure area. Fueled by the heat and evaporating water from the ocean, an engine of swirling cloud and wind was heading westward—in the direction of the Philippines.

In the next few days, the newly formed tropical cyclone continued to grow and gain strength, powered by the warmer-than-usual waters of the Pacific. The Hawaii-based Joint Typhoon Warning Center (JTWC) said the tropical disturbance “intensified at an above average rate” as it passed south of Guam, followed by “explosive deepening” as its intensity almost doubled within 24 hours.

Yolanda: Storm of the century

It was given the name “Haiyan.” (Once inside the Philippine Area of Responsibility, or PAR, it would bear the name “Yolanda.”)

On Nov. 5, the JTWC warned that Haiyan would turn into a super typhoon with peak intensity of 130 knots or 241 kph.

Yolanda entered PAR on Nov. 7. On Nov. 8, Yolanda made its first landfall, in Guiuan, Eastern Samar.

The JTWC estimated that Yolanda reached one-minute sustained winds of 315 kph just minutes before landfall, making it, at that time, the most powerful tropical cyclone to ever hit land.

BACKSTORY:
One of world’s strongest typhoons lashes Philippines
Top 7 Deadliest and Most Destructive Typhoons Since 1970

History’s strongest

Tropical cyclones form in warm waters—with a temperature of at least 26.5 degrees Celsius—and with a minimum distance of at least 500 kms from the equator (US National Oceanic and Atmospheric Administration or NOAA).

In Yolanda’s case, the above-average temperature of the Pacific Ocean and the lack of wind shear, which often prevents typhoon formation, contributed to its intensity.

In fact, NOAA reported that the combined land and sea surface temperature in November 2013—at 0.78 degrees above the 20th century average of 12.9 degrees for the month of November—was the highest in the previous 134 years.

Sea surface temperature, which NOAA refers to as the skin temperature of ocean surface water, for November that year was third highest (tied with 2009) at 0.54 degrees above the 20th century average of 15.8 degrees.

In other words, conditions for the formation of a super typhoon like Yolanda late in the year were at among their ripest in recorded history.

The JTWC’s Annual Tropical Cyclone Report for 2013 supports this view, as it recorded sea surface temperature along the super typhoon’s track exceeding 29 degrees.

“Along-track ocean heat content (OHC) was also very high, indicating that warm water extended fairly deep into the upper-ocean along the cyclone’s path,” the report noted.

Low vertical wind shear (VWS) was also observed by the University of Wisconsin Cooperative Institute for Meteorological Satellite Studies.

“Strong radial outflow, low VWS, and warm ocean waters provided favorable conditions for the initial rapid intensification to typhoon strength, and subsequent explosive deepening from minimal typhoon intensity (70 knots or 130 kph) to super typhoon intensity (130 knots or 241 kph) during the following 24 hours,” the JTWC said.

Increased warmth

Professor Jim Elsner of the Florida State University and Namyoung Kang, the deputy director of the National Typhoon Center in South Korea, published a relevant study last year. They found that, in the last 30 years, there were about six fewer tropical cyclones per year, but packed winds were stronger by three miles (or almost five kms) per hour.

It is “a tradeoff between frequency and intensity,” Elsner told Science Daily.

Brian Caccioppoli, in his review of Elsner and Kang’s study, said the most important aspect of the study was the proposed “mechanism” for the said trade-off.

“The increased warmth in the surface ocean leads to more evaporation of moist air to the lower-most atmosphere, but warmer and drier conditions (strong high pressure) exist just above acting as a barrier to moisture and tropical cyclone formation. This atmospheric configuration is unstable, so storms that are able to overcome the high pressure barrier are greeted with conditions ripe for efficient intensification.”

In other words: Stronger storms.

Storm surges

Yolanda struck the eastern coast of Leyte with so much force its winds obliterated houses made of light material and generated a series of storm surges that washed out communities and coconut plantations.

Residents of Guiuan recalled being caught up in tornado-like winds. In Hernani town, Maricel Jerusalem and her family evacuated to her cousin’s house, thinking a concrete two-storey structure would save them from the super typhoon. But the tsunami-like waves crept inland and rose as high as 15 feet. Clutching her two-week old baby, Maricel swam towards higher ground. The baby survived but not Maricel’s 11-year-old brother, who was “swallowed by the waves.”

BACKSTORY
Guiuan folk: How shall we live?
2 weeks after `Yolanda’, tragic tales still haunt Hernani folk

Yolanda made its second landfall in Leyte.

Gerald Villamor described the storm surge that destroyed his village and killed thousands of people in Tacloban City in this way: “Three large waves that were so high we lost sight of Samar Island.” He watched on the roof of his house as the coastal villages and the airport of Tacloban were submerged in dark water, a murky soup of debris, mud and corpses.

Yolanda accelerated and in a matter of hours struck Cebu’s Daanbantayan and Bantayan Island. It reached Concepcion, Iloilo in Panay Island by noon, threatening fishing communities and damaging transmission lines.

According to the Japan Meteorological Agency, Yolanda had lasted for 7 days or 174 hours before finally dissipating in the area of China.

In its passage through central Philippines, Yolanda ravaged nine regions, causing the deaths of 6,300 people, the displacement of 3.4 million families, and the destruction of 489,613 houses–as well as sustaining P89 billion in damages.

In faraway Warsaw, Christiana Figueres, chief of the UN Framework Convention on Climate Change, offered a grim assessment. The super typhoon was part of the “sobering reality” of climate change.

Note: The Inquirer Group is covering the historic climate change conference in Paris, which starts Nov. 30. This special report is part of the Group’s PINAS TO PARIS campaign.

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