 Severe Tropical Storm Washi approachingMindanao on December 16 | |
| Meteorological history | |
|---|---|
| Formed | December 13, 2011 |
| Dissipated | December 19, 2011 |
| Severe tropical storm | |
| 10-minute sustained (JMA) | |
| Highest winds | 95 km/h (60 mph) |
| Lowest pressure | 992hPa (mbar); 29.29 inHg |
| Tropical storm | |
| 1-minute sustained (SSHWS/JTWC) | |
| Highest winds | 95 km/h (60 mph) |
| Lowest pressure | 985hPa (mbar); 29.09 inHg |
| Overall effects | |
| Fatalities | 1,292–2,546[1][2] |
| Injuries | 6,071[3] |
| Missing | 1,049[1] |
| Damage | $97.8 million (2011USD) |
| Areas affected | Caroline Islands,Philippines |
IBTrACS | |
Part of the2011 Pacific typhoon season | |
Severe Tropical Storm Washi, known in the Philippines asSevere Tropical Storm Sendong, was a late-seasontropical cyclone that caused around 1,200 to 2,500 deaths and catastrophic damage in thePhilippines in late 2011. Washi made landfall overMindanao, a major region in the Philippines, on December 16. Washi weakened slightly after passing Mindanao, but regained strength in theSulu Sea, and made landfall again overPalawan on December 17.
Extratropical cyclone, remnant low, tropical disturbance, or monsoon depressionOn December 12, theJoint Typhoon Warning Center (JTWC) noted that a developingarea of low pressure had persisted about 945 km (585 mi) south-southeast ofGuam. Situated along the southern edge of asubtropical ridge, the system tracked steadily westward towards thePhilippines. Located within a region of gooddiffluence and moderatewind shear, deepconvection was able to maintain itself over the circulation. Development ofbanding features and improvement ofoutflow indicated strengthening was likely.[4] Furtherdevelopment over the following day prompted the JTWC to issue aTropical Cyclone Formation Alert early on December 13.[5] Less than six hours later, both the JTWC and theJapan Meteorological Agency (JMA) classified the system as a tropical depression, with the former assigning the identifier27W.[6] Maintaining a westward track, the depression was forecast to intensify slowly over the following three days.[7] For much of December 13, a slight increase in shear displaced thunderstorm activity from the center of the depression, delaying intensification. By December 14, convection redeveloped over the low and the JTWC subsequently assessed the system to have attained tropical storm status.[8]
Early on December 15, the system crossed west of135°E and entered thePhilippine Atmospheric, Geophysical and Astronomical Services Administration's (PAGASA) area of responsibility. Upon doing so, PAGASA began issuing advisories and assigned the cyclone with the local nameSendong.[9] Shortly thereafter, the storm passed close to or overPalau.[10] By 0600 UTC, the JMA upgraded the system to tropical storm status, at which time they assigned it with the nameWashi.[11] Maintaining a rapid westward track, Washi slowly became more organized, with low-level inflow improving during the latter part of December 15.[12] On December 16, Washi reached its peak strength as a severe tropical storm and made its firstlandfall along the east coast ofMindanao.
After passing Mindanao, Washi weakened due to land interaction, but the storm quickly regained its strength, in theSulu Sea. Late on December 17, Washi crossedPalawan and arrived in theSouth China Sea, and the system moved out of thePAR on December 18. Washi weakened to a tropical depression and dissipated on December 19, because of cool, dry air, in association with theNortheast Monsoon.
Across theCagayan de Oro river basin, a localized heavy rain event occurred during Tropical Storm Washi's passage.[3] Onshore flow fromMacajalar Bay, which the Cagayan de Oro river drains into, ran into the steep terrain ofMount Makaturing,Mount Kalatungan, andMount Kitanglad, resulting in orographic enhancement of precipitation. A weather station in Capehan located along the Bubunawan river, a tributary of the Cagayan de Oro river, recorded 475 mm (18.7 in) over a 24‑hour span.[1] The rainfall event itself amounted to a1-in-20 year event for much ofMisamis Oriental.[13] In the span of 24 hours, 180.9 mm (7.12 in) of rain fell atLumbia which equates to more than 60 percent of their average December precipitation.[3] Estimates from theTropical Rainfall Measuring Mission jointly run byNASA andJAXA indicated that accumulations around the Cagayan de Oro river exceeded 400 mm (16 in).[14] Observations fromTalakag captured the sheer intensity of rainfall associated with Washi, with hourly accumulations peaking at 60.6 mm (2.39 in). Similar amounts, though less anomalous in magnitude, fell farther east on Mindanao. Satellite estimates indicated accumulations of 200 to 250 mm (7.9 to 9.8 in) along coastal areas near where Washi made landfall.[14] A total of 180.4 mm (7.10 in) was observed inHinatuan.[3]
Starting in tributaries and later reaching the main Cagayan de Oro, Iponan, and Mandulog rivers,flash flooding manifested at a dramatic pace.[1] In some locations, flood waters rose by 3.3 m (11 ft) in less than an hour.[15] Alongside the effects from rainfall, high tide at Macajalar Bay further enhanced the flood event and allowed water to inundate areas that would have otherwise safe at low tide. The rivers crested at 7 to 9 m (23 to 30 ft), amounting to a75-year flood event in some areas, with catastrophic results.[3][1] This was also far higher than the previous flood event followingTropical Depression Auring in January 2009. Located outside the main "typhoon belt," residents in the affected areas suffered from a false sense of security with tropical cyclone related disasters. Flooding from the rivers struck at approximately 2:30 a.m. local time, when most people were asleep and unable to hear warnings from PAGASA. Hardest hit were the cities ofCagayan de Oro andIligan where tremendous loss of life occurred. Within Cagayan de Oro, thebarangay ofBalulang,Carmen andMacasandig was virtually wiped out. Between the two cities, 1,147 people lost their lives while a further 1,993 sustained injury.[1] Residents affected by these flood waters were forced to seek refuge on their roofs amidst 90 km/h (55 mph) winds. The mayor of Iligan regarded the floods as the worst in the city's history.[16]
Throughout the affected areas, nearly 40,000 homes were damaged of which 11,463 were destroyed. Nearly 700,000 people were affected by the storm.[1] Total casualties attributed to the event are uncertain, with theNational Disaster Risk Reduction and Management Council's final report in February 2012 stating 1,268 fatalities, 181 people missing, and 6,071 injuries.[3] A later report by theWorld Meteorological Organization in December of that year indicated 1,292 deaths, 1,049 missing, and 2,002 injured.[1] TheInternational Federation of Red Cross and Red Crescent Societies stated a total of 2,546 deaths in their final report on August 21, 2013.[2][17][18][better source needed] Damage directly related to the storm amounted to₱ 2.068 billion (2012 PhP, $48.4 millionUSD). Over half of the damage was due to damaged roads and bridges.[3] Total socio-economic losses amounted to US$97.8 million.[1]
| PSWS# | Luzon | Visayas | Mindanao |
|---|---|---|---|
| 2 | Palawan | Southern Leyte, Bohol, Southern portion of Cebu, Southern portion of Negros Oriental, Southern Portion of Negros Occidental, Siquijor | Surigao del Norte incl. Siargao Island, Surigao del Sur, Dinagat Province, Agusan del Norte, Agusan del Sur, Davao del Norte, Davao Oriental, Samal Island, Lanao del Norte, Lanao del Sur, Misamis Occidental, Misamis Oriental, Zamboanga del Norte, Zamboanga del Sur, North Cotabato, Compostela Valley, Camiguin, Bukidnon, Maguindanao, Camotes Islands |
| 1 | Masbate, Sorsogon, Ticao Islands, Cuyo Islands, Coron | Eastern Samar, Western portion of Samar, Northern portion of Leyte, Rest of Cebu, Rest of Negros Oriental, Rest of Negros Occidental, Capiz, Antique, Aklan, Iloilo, Guimaras | None |
| Rank | Storm | Season | Fatalities | Ref. |
|---|---|---|---|---|
| 1 | Yolanda (Haiyan) | 2013 | 6,300 | [19] |
| 2 | Uring (Thelma) | 1991 | 5,101–8,000 | [20] |
| 3 | Pablo (Bopha) | 2012 | 1,901 | [20] |
| 4 | "Angela" | 1867 | 1,800 | [21] |
| 5 | Winnie | 2004 | 1,593 | [21] |
| 6 | "October 1897" | 1897 | 1,500 | [21][22] |
| 7 | Nitang (Ike) | 1984 | 1,426 | [23] |
| 8 | Reming (Durian) | 2006 | 1,399 | [21][20] |
| 9 | Frank (Fengshen) | 2008 | 1,371 | [nb 1][24][25] |
| 10 | Sendong (Washi) | 2011 | 1,257 | [26] |
A massive relief operation involving the evacuation of 100,000 people occurred on the morning of December 17, 2011. Approximately 20,000 soldiers were mobilized to assist in recovery efforts and evacuations.[16] ThePhilippine Coast Guard was dispatched to search for missing people after villages were reported to have been swept out to sea. Sixty people were rescued off the coast ofEl Salvador, Misamis Oriental and another 120 in the waters nearOpol township.[27] PresidentBenigno Aquino III visitedCagayan de Oro andIligan on December 20, 2011, and declared astate of national calamity in the affected provinces.[28] The President also appealed to its citizens to help the victims in their way of celebratingChristmas in his Christmas Message.[29]
Aleptospirosis outbreak in the immediate aftermath infected more than 400 people and killed 22. Additional fatalities from suicide took place in evacuation centers, though exact numbers are unknown.[1]
In the three years following Washi, ₱2.57 billion (US$58 million) was allocated to build 30,438 shelters, designed to withstand winds of 220 km/h (140 mph), in eight regions. Less than half of this total had been built by December 2014, though construction inCagayan de Oro andIligan was largely complete.[30] The storm prompted a shift in settlement patterns in Cagayan de Oro, with residents moving away from the areas along theCagayan River in favor of upland areas.[31]
Overseas humanitarian aid was sent to victims of Washi in the Philippines.
TheAustralian government provided A$1 million (US$1.01 million) in financial aid.[32]
TheDanish government provided 300,000 DKK (US$53,000) in emergency funds for relief items such as food, water, sanitation materials, mattresses and blankets.[33]
TheEuropean Commission allocated€3 million ($3.9 million) to provide emergency relief to tens of thousands of people affected by the storm.[34]
TheFrench Government provided €50,000 (US$65,000) in emergency funds.[35]
TheGovernment of Indonesia provided $50,000 in financial aid and offered to send search and rescue teams and medical teams.[32]
TheJapanese government provided 25 millionyen (US$320,000) worth of relief goods, such as water tanks and generators, for victims of the storm.[35]
TheGovernment of Malaysia provided $100,000 in financial assistance for relief and rehabilitation.[35]
TheChinese government provided $1.1 million in financial aid.[32]
TheGovernment of Singapore provided S$50,000 (US$39,000) in funds and S$27,800 (US$22,000) worth of relief goods.[32]
TheGovernment of South Korea provided $500,000 in financial aid.[32]
Six members of the Swiss Humanitarian Aid Unit were sent to Mindanao to ensure access to clean drinking water.[36]
TheBritish Red Cross provided £140,000 (US$220,000) in funds to support relief efforts.[37]
On December 21, the United Nations Emergency Relief Agency released $3 million in funds to improve water and sanitation. On December 22, theUnited Nations Department of Humanitarian Affairs announced a plan to raise $26.8 million in aid for victims of Severe Tropical Storm Washi.United Nations Secretary-GeneralBan Ki-moon sympathized with the Philippine Government and stated "the [United Nations] would extend whatever help is needed by those who were affected by the disaster."[35] The United Nations High Commissioner for Refugees also pledged to send 42 metric tons of aid to the country.[32] TheUnited Nations Children's Fund also appealed for $4.2 million to be sent to the Philippines.[38]
TheUnited States provided $100,000 in funds to support relief efforts. The country's ambassador,Harry K. Thomas Jr., expressed his "heartfelt condolences and sympathies" to those affected by the storm. Immediate assistance was to be provided by theUnited States Agency for International Development'sOffice of Foreign Disaster Assistance. Non-food items such as hygiene kits, water purification tablets, and containers were to be sent to the Philippines.[39]
Due to its high death toll, PAGASA announced that the name,Sendong, would be retired from their tropical cyclone naming lists.[40] In June 2012, PAGASA selected the nameSarah to replaceSendong for the2015 season. However, due to fewer tropical cyclones entering the area that season, it was first used only in the2019 season.[citation needed]
In February 2012, the ESCAP/WMO Typhoon Committee announced thatWashi would also beretired from its naming lists and was replaced with the nameHato. But the name Hato was also retired in 2017 and was replaced withYamaneko, which was first used in the2022 season.[41]
Tropical cyclones of the2011 Pacific typhoon season | ||
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