Typhoon Ketsana, known in the Philippines as Tropical Storm Ondoy was a catastrophic tropical cyclone that caused extensive damages across Southeast Asia, particularly in the Philippines and Vietnam. It is both the second deadliest and costliest typhoon of the 2009 Pacific typhoon season, with at least $1.15 billion in damages, trailing behind Morakot with damages worth $6.2 billion, and 921 fatalities.
The sixteenth tropical storm and eighth typhoon of the season, Ketsana formed early about northwest of Palau on September 23, 2009. Initially, it was downgraded to a low pressure area by the Japan Meteorological Agency (JMA), but after drifting through favorable conditions, it intensified the next day and was categorized as a tropical depression by the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), and was given the name Ondoy after entering the Philippine Area of Responsibility. The Joint Typhoon Warning Center (JTWC) issued a Tropical Cyclone Formation Alert on the depression. It was then upgraded to a tropical depression by the JMA later that morning before the JTWC followed suit early on September 25, designating the depression as 17W. Soon, the depression strengthened into a tropical storm, and was given the name Ketsana by the JMA. Shortly after, it made landfall over the Philippines, and as it moved into the South China Sea, the storm intensified while moving towards the west. It peaked as a Category 2-equivalent typhoon before ultimately making landfall on Vietnam at peak intensity on September 29, dissipating on the next day.
While Ketsana made landfall north of Metro Manila as a tropical storm, it enhanced the southwest monsoon, bringing record-breaking rainfall and flooding across the Philippines' capital. At least 464 deaths and $237 million (₱11.1 billion) were attributed to the typhoon, making it the most devastating tropical cyclone to hit Metro Manila, surpassing Typhoon Patsy (Yoling) in 1970. Flood water levels also reached a record in rural areas. In response to this, President Gloria Macapagal Arroyo declared a "state of calamity" encompassing most of Luzon after at least 86 people were initially reported dead in landslides and other incidents. Recovery efforts from the storm's onslaught would later be hampered by Typhoon Parma, which made landfall in the Philippines roughly a week after Ketsana.
Meteorological history
On September 23, 2009, the Japan Meteorological Agency (JMA), reported that a seasonal tropical depression had formed about to the northwest of Palau. The Joint Typhoon Warning Center (JTWC) then reported later that day that the depression had a developing low-level circulation center and was in a favorable environment with low vertical wind shear. The JMA then reported that the depression had weakened into an area of low pressure. However, early the next day, as deep convection started to consolidate around the low-level circulation center, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) reported that the low-pressure area had become a tropical depression and assigned it a local name of Ondoy. Later that morning, the JTWC issued a Tropical Cyclone Formation Alert as central convection had continued to organize around a consolidating elongated but exposed low-level circulation center. The JMA then re-upgraded Ondoy to a tropical depression later that morning before the JTWC followed suit early on September 25, designating it as Tropical Depression 17W when it was located about 400 nm east of Manila in the Philippines. At this stage, the system was moving along the southern side of the subtropical ridge and had good poleward outflow into a tropical upper tropospheric trough (TUTT) cell.
Throughout September 25 the intensification of Ondoy was hampered by the system moving into an area of moderate vertical wind shear and by an upper-level trough of pressure that was moving over the system. But later that day the JTWC upgraded it to a tropical storm despite its low level circulation center being partially exposed. The JMA followed suit early the next day, assigning the international name of Ketsana and the international designation of 0916 to the storm. PAGASA then reported that Ketsana had made landfall on Northern Luzon near the boundary of the Philippine provinces of Aurora and Quezon. As a result of making landfall, its low-level circulation center had become fully exposed, but as the storm moved into the South China Sea, it dramatically deepened and expanded while moving west and was upgraded to a severe tropical storm by the JMA early on September 27.
During September 27, Ketsana gradually developed further and was upgraded to a typhoon by the JTWC and the JMA early the next day, as multiple convective bands were continuing to consolidate more tightly around the low-level circulation center, leading to the formation of a disorganized eye. Typhoon Ketsena then intensified quickly under favorable conditions, reaching peak windspeeds later that day of (1-min winds) and (10-min winds) which made it a Category 2 typhoon on the Saffir–Simpson scale. Ketsana then made a second landfall on Quảng Nam in Vietnam, at 0600 UTC on September 29 at its peak intensity. It then rapidly weakened into a Severe Tropical Storm, with the JTWC issuing its last advisory later that day; however, the JMA continued to monitor Ketsana as a Severe Tropical Storm until later that day, when it downgraded it to a Tropical Storm before further downgrading it to a Tropical Depression early the next day when the center of the depression was located over Laos. The JMA monitored the storm as a weak tropical depression until late on September 30, when it released its final advisory.
Preparations
Philippines Highest Public Storm Warning Signal
PSWS# Luzon Visayas Mindanao2Pangasinan, Nueva Vizcaya, Quirino, Aurora, Nueva Ecija, Zambales, Tarlac, Pampanga, Bulacan, Northern portion of Quezon including Polillo IslandNoneNone1Metro Manila, Bataan, Rizal, Cavite, Laguna, Batangas, Camarines Norte, Marinduque, Mindoro Provinces, Lubang Island, Ilocos Sur, La Union, Benguet, Isabela, Mt. Province, Ifugao, Southern portion of QuezonNoneNone
On September 24, the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA) placed the provinces of Aurora, northern Quezon, Camarines Norte, Camarines Sur, and Catanduanes under Public Storm Warning Signal (PSWS) No. 1, which meant that winds of were expected to affect those areas within 36 hours. PAGASA raised PSWS No. 2 for the provinces of Catanduanes, Camarines Norte and Camarines Sur, and Polillo Island in Quezon. On September 28, PAGASA lifted all public storm signals in the country as Ketsana left the Philippine Area of Responsibility (PAR) the same day. After the floods struck, some were critical of the government's failure to predict the scale of the disaster or to lessen the damage it caused.
China Late on September 27, both the Hong Kong Observatory and the Macao Meteorological and Geophysical Bureau placed Hong Kong and Macau under the Standby Signal No.1. The Bureau then considered hoisting the Strong Wind Signal 3, but decided it was not needed for Hong Kong, while Macau hoisted it early the next day. These warnings were kept in force until later that day when all warnings were lowered. On September 29 it was announced that parts of southern China would be placed under an orange warning with certain regional meteorological bureaus entering a level 3 emergency response.
Vietnam On September 27, the Vietnam National Center for Hydro-Meteorological Forecasting issued a public storm warning signal named "Number 9." The Vietnamese government evacuated some 170,000 people. The government instructed residents to secure their homes with fortified hard wood and sandbag roofs. Also, authorities mobilized several thousand military personnel and police to help residents evacuate from the typhoon's path. Fishing vessels were called to return to their ports. This caused thousands of crops to fail.
Impact
Philippines + Typhoon Ketsana casualties in the Philippines NDCC death tallyRegion DeathsCAR4Region III56NCR448Region IV-A160ARMM3Total671 DamagesAmount Agriculture ₱6,766,046,143.00($143,805,444.06) Infrastructure ₱4,391,462,577.60($93,336,080.29) Total damagesTotal damages figure includes agriculture, infrastructure, casualties, etc. damages. ₱11,157,508,720.60($237,141,524.35)
Tropical Storm Ondoy (Ketsana) Rainfall Distribution over Philippines Measurementstation Precipitation Date Pre-Post(mm) (mm) (in) PAGASA Science Garden, Quezon City, NCR 454.9 mm 17.91 inches September 26, 2009 94.0 mm Tanay, Rizal, CALABARZON 331.7 mm 13.06 inches September 26, 2009 41.5 mm Manila, Metro Manila, NCR 258.6 mm 10.18 inches September 26, 2009 41.4 mm Ambulong, Batangas/Laguna, CALABARZON 234.4 mm 9.23 inches September 26, 2009 49.5 mm Bagasbas, Daet, Camarines Norte, Bicol 204.5 mm 8.05 inches September 25, 2009 5.8 mm Infanta, Quezon, CALABARZON 176.2 mm 6.94 inches September 26, 2009 98.6 mm (PSW), Barrio Barretto, Zambales, Central Luzon 159.3 mm 6.27 inches September 26, 2009 75.2 mm Subic, W.S., Zambales, Central Luzon 127.8 mm 5.03 inches September 26, 2009 50.3 mm Clark AFB, Angeles City, Pampanga, Central Luzon 109.0 mm 4.29 inches September 26, 2009 25.4 mm Iba, Zambales, Central Luzon 103.9 mm 4.09 inches September 26, 2009 39.9 mm
Ketsana caused widespread flash flooding in the cities of Manila, Caloocan, Marikina, Malabon, Muntinlupa, Quezon, Makati, Pasay, Pasig, Taguig, Valenzuela, and San Juan. Flooding also occurred in the nearby provinces of Bulacan, Rizal, Laguna, and other Calabarzon areas. Major roads were rendered impassable because of huge flood currents and clogged cars. Air flights were canceled because of heavy rains.
Earlier, power interruptions were reported in Camarines Norte, and minor landslides occurred in Camarines Sur.
EDSA was closed because of heavy flooding. Defense Secretary and National Disaster Risk Reduction and Management Council (NDCC) chairman Gilbert Teodoro asked the DOTC to keep MRT and LRT lines operational to accommodate stranded passengers. On the afternoon of September 26, Gilbert Teodoro declared an overall state of calamity in Metro Manila and the nearby 25 provinces in Luzon hit by the typhoon, allowing officials to utilize emergency funds for relief and rescue. Army troops, police, and civilian volunteers were deployed to rescue victims. The Philippine National Red Cross and the Philippine Coast Guard dispatched teams to rescue stranded and trapped people. At that time, the average height of flooding was from two feet to waist high, and in some areas above six feet. Even Malacañang Palace was opened to those who were in need. The landslides and severe flooding left at least 246 people dead and 38 others missing. Public and private roads were clogged by vehicles stuck in floodwater. Thousands of motorists and more than 500 passengers were stranded at the North Luzon Expressway (NLEx). Distress telephone calls and emails from thousands of Metro Manila residents and their worried relatives flooded television and radio stations overnight as most of the power supply, communication, and water supply were lost. Ketsana also caused Ninoy Aquino International Airport (NAIA) to close for almost a day.
The economic region of Metro Manila and many adjoining provinces incurred damages to both infrastructure and agriculture. As of September 28, 2009, total damages from Ketsana were estimated at $100 million. Internet cafés, entertainment plazas, banks, food stores, building agencies, and stores were soaked with water and mud. Many people were warned of leptospirosis.