Typhoon Bopha, named Pablo by PAGASA, was a compact but powerful and catastrophic tropical cyclone that became the strongest on record to ever affect the Philippine island of Mindanao, making landfall as a Category 5 super typhoon with winds of 175 mph (282 km/h). The twenty-fourth tropical storm, along with being the fourth and final super typhoon of the 2012 Pacific typhoon season, Bopha originated unusually close to the equator, becoming the second-most southerly Category 5 super typhoon, reaching a minimum latitude of 7.4°N on December 3, 2012, as only Typhoon Louise of 1964 came closer to the equator at this strength, at 7.3°N. After first making landfall in Palau, where it destroyed houses, disrupted communications and caused power outages, flooding and uprooted trees, Bopha made landfall late on December 3 in Mindanao. The storm caused widespread destruction on Mindanao, leaving thousands of people homeless and killing 1,901 people.
After hitting Davao Oriental and Davao de Oro provinces, Bopha shifted through the southern and central regions of Mindanao, cutting power to two provinces and triggering landslides. More than 170,000 people fled to evacuation centers, as the system moved to the South China Sea west of the Palawan island province, eventually dissipating on December 9.
Meteorological history
On November 23, the United States Joint Typhoon Warning Center (JTWC) reported that a tropical disturbance had persisted, about 650 km (405 mi) to the south of Pohnpei in the Federated States of Micronesia. At the time, bands of atmospheric convection were flaring around the disturbances poorly defined low-level circulation centre, while the system was located in an area of moderate vertical windshear with sea-surface temperatures of 28–30 °C (82–86 °F). Over the next couple of days, the system's low-level circulation centre slowly consolidated further and came under the influence of a developing anticyclone, which allowed vertical windshear to become more favourable for tropical cyclogenesis. On November 25, the JTWC and the Japan Meteorological Agency (JMA) reported that disturbance had developed into a tropical depression, with the former classifying it as Tropical Depression 26W. At this time the system was located about 530 km (330 mi) to the southeast of Chuuk State and was moving towards the west-northwest, along the southern edge of a subtropical ridge of high pressure that was located to the south of Japan.
On November 26, the movement became nearly stationary as the center organized further. Later that day, the JMA upgraded the depression to a tropical storm named Bopha (1224), and early on November 27 the JTWC followed suit after a strong burst of thunderstorms over the center. Its westward motion increased on November 28, later becoming west-southwestward. The convection gradually became better organized and wrapped into the center, indicative of a strengthening storm. However, early on November 29 the appearance degraded, with the thunderstorms limited to the southern periphery due to reduced outflow to the south. The circulation became exposed, and the JTWC noted that Bopha was unable to intensify significantly due to its low latitude and correspondingly low Coriolis effect. Late on November 29, convection increased, aided by warm waters and low wind shear. At 00:00 UTC on November 30, the JMA upgraded Bopha to a severe tropical storm. A few hours later, the JTWC upgraded the storm to a typhoon, and the JMA followed suit at 18:00 UTC that day. At that time, Bopha was located about 980 km (610 mi) east-southeast of Palau.
As the system continued to intensify, organized bands of thunderstorms began to develop rapidly around the system, mostly on the western half of the storm. They later merged with Bopha, which led to the system's increase in size. Several hot towers also began to rise up near the low level circulation center, with one of the hot towers reaching 17 km (11 mi) into the atmosphere. At around the same time, on November 30, a ragged, eye-like feature appeared in microwave imagery, which later transitioned into a pinhole eye by December 1. The stadium effect was also observed in the thick convection surrounding the eyewall, involving thin strips of clouds from the eyewall curve outward from the surface with height. At around the same time the system's eye structure improved, it began to explosively intensify, becoming a Category 4 storm in 18 hours, while being less than five degrees from the equator.
On December 1, the system, as a Category 4 typhoon, maintained a well defined, small eye, which later dissipated, but reformed by December 2. As Bopha strengthened further into a super typhoon on December 2, the well-defined eye underwent a small eyewall replacement cycle by late December 2, and by 10:00 UTC on December 2, the system developed double eye walls, which were only seen in microwave imagery. AT 12:30 UTC on December 2, Bopha neared Palau, with a closest distance of 50 km (31 mi). At that time, the system's outflow improved, and convection near the eye thickened. Early on December 3, due to the eye wall replacement cycle, the system weakened slightly into a Category 3 typhoon; however, a few hours later, as the eyewall replacement cycle ended, Bopha reintensified into a Category 4 typhoon, while the eye became well-defined again. Late on December 3, as the system continued to strengthen, the system rapidly intensified into a Category 5 super typhoon, deepening to an unofficial pressure of 918 mbar (hPa) (27.11 inHg) as stated by the JTWC at peak intensity, as the eye started to become well defined at 27 km (17 mi) across. The system's convection also became more compact and organized. At that time, an anticyclone located northeast of Bopha continued to provide ample radial outflow and low vertical wind shear over the system, causing favorable conditions, leading to its re-intensification.
At 20:45 UTC on December 3 (04:45
December 4 local time), Bopha made landfall over Baganga, Davao Oriental, as a Category 5 super typhoon, and the eye dissipated just an hour after landfall. Bopha began to weaken, with convection on the eastern side of the storm decreasing as it moved through the Sulu Sea. It made landfall on the island of Palawan on December 5, before briefly weakening to a tropical storm on December 6. The JMA continued tracking the system as a typhoon. Overnight, the convection around the storm center weakened, but made another burst on December 7, with an eye-like feature shown only in microwave imagery. After a few hours, the system reintensified into a Category 1 typhoon and developed a 27 km (17 mi), well defined eye.
Late on December 7, Bopha's central dense overcast started to increase slightly, and the typhoon rapidly intensified from a Category 1 to a Category 4 typhoon in only six hours. Upon reintesifying, Bopha developed a well-defined eye that had deep convection near the center of the storm. On December 8, the system started to weaken due to increasing moderate wind shear. Late on December 8 into December 9, Bopha weakened rapidly from a typhoon to a tropical storm, with its convection being blown to the northeast by wind shear, exposing the low level circulation center. The remaining thin convection in the center consisted of few convective thunderstorms associated with stratocumulus clouds.
Preparations
Caroline Islands
As Bopha was organizing, the National Weather Service (NWS) in Guam issued a tropical storm watch for the FSM islands of Nukuoro and Lukunor. The watch was upgraded to a tropical storm warning on November 26, and the watch was expanded to include Losap and Chuuk Lagoon. As Bopha moved westward, the office also issued a tropical storm watch for Poluwat, and Satawal, both of which were upgraded to warnings, and a typhoon watch was issued for Woleai.
The Palau National Emergency Management Office (NEMO) issued an announcement on November 29 requesting the public to stock up with emergency supplies such as food and water for three days, portable radios with spare batteries, flashlights, and first-aid kits. The citizens of Palau were also advised to secure loose objects that might be lifted up by the strong winds, board up windows, trim tree branches that could fall and damage homes, fill up vehicles with gas, secure boats and assist their communities in preparing.
Philippines
Highest Tropical Cyclone Wind Signal
Initially, the National Disaster Risk Reduction and Management Council (NDRRMC) advised the citizens of Iligan and Cagayan de Oro to prepare for the impact of the storm, as they really did not want a repeat of Severe Tropical Storm Washi, which had hit when people were asleep and, therefore, had caused a large number of deaths. On December 2, the NDRRMC put parts of the central and southeastern Philippines on high alert. Relief food and medicines had been pre-positioned while thousands of people along the country's eastern border were being prepared for evacuation to safer ground in preparation for the typhoon. With Bopha expected to strike Mindanao and Visayas, as well as areas in Southern Tagalog and Metro Manila, the possibility of landslides was advised in Surigao, Davao, Compostela Valley, Misamis, Bukidnon, Lanao del Norte, Lanao del Sur, Zamboanga, Leyte, Cebu, Bohol, Negros, Panay and Mindoro. "Keep updated on the bulletins from PAGASA. Always cooperate with the local authorities as the National Government is all ready to provide all assistance to those that may be affected," Valte said. Also, disaster authorities in Bicol were alerted and getting ready with their disaster contingency plan as the typhoon was closing in.On December 3, around 2,000 families living in Hinatuan, on the province of Surigao del Sur, were evacuated. Since schools would be turned into evacuation centers, Candelario Viola, the mayor of Hinatuan, ordered the suspension of all classes in the town. Mar Roxas, the Interior and Local Government Secretary, said that National Disaster Risk Reduction and Management Council’s disaster monitoring systems were set up in several regions across the Philippines. "In accordance with President Aquino’s marching orders to ensure zero casualties from disasters, as much as possible, I have ordered our regional directors to make sure that the necessary precautions are undertaken to mitigate the effects of Tropical Storm Bopha," he said. "We have our existing protocols, and it is just a matter of implementing them and making other necessary preparations as appropriate." Roxas added. As preparations continued, Storm signal number 1 was declared over Siquijor, Bohol, Biliran, Camotes Island, Cebu Southern Leyte, Leyte, Eastern Samar, Western Samar, Surigao del Norte, Siargao Island, Dinagat Island, Agusan del Norte, Agusan del Sur, rest of Davao Oriental, Davaol del Norte including Samal Island, Compostela Valley, Bukidnon, Misamis Occidental, Misamis oriental, Camiguin, Lanao del Norte and Lanao del Sur. Also, signal number 2 was raised over Surigao del Sur and the northern part of Davao Oriental. The national police, coast guard (PCG) and navy had placed their personnel on standby and their disaster-response units in preparation for Bopha's impact. "We are ready to conduct rescue operations in flooded areas. Let us warn operators of small vessels, motor bancas, and fishing boats to avoid sailing in the southeastern and eastern section of the country where the sea is rough," said PCG spokesman Commander Armand Balilo. After staying in the South China Sea for at least 4 days, "Pablo" again threatened the western sections of Northern Luzon, and by the afternoon of December 8, public storm warning signal number 2 was raised over 3 provinces, and 11 provinces were inside signal number 1. Forecasters said the storm had turned and is due to hit the Philippines on December 9.
Impact
Caroline Islands
As Typhoon Bopha passed to the south of the island, power outages occurred across the island chain. Communication network disruptions delayed updates on damage assessments after the storm passed. Initial damage assessments in Koror indicated slight damage, with uprooted trees and power disruption. Outside of Koror, coastal villages were affected by strong winds and rain, which flooded outlying areas. Heavy rains flooded areas of Peleliu, and houses in Babeldaob were destroyed.