Typhoon Chanchu
Typhoon Chanchu, known in the Philippines as Typhoon Caloy, was the most intense typhoon in the South China Sea in the month of May according to the Hong Kong Observatory. The first named storm of the 2006 Pacific typhoon season, Chanchu formed on May 8 in the vicinity of the Federated States of Micronesia and progressed westward. It gradually intensified into a tropical storm and later severe tropical storm before moving through the Philippines. On May 13, Chanchu entered the South China Sea and became a typhoon, according to the Japan Meteorological Agency. Warm waters and favorable outflow allowed the storm to quickly intensify to peak maximum sustained winds of on May 15. Around that time, the typhoon turned sharply to the north toward southeastern China. Chanchu weakened as it curved to the northeast, making landfall near Shantou, Guangdong on May 17 as a severe tropical storm. The government of China considered Chanchu the earliest typhoon to make landfall in the province. On the next day, the storm emerged into the East China Sea, becoming extratropical on May 19 before dissipating west of Kyushu.
Early in its duration, Chanchu moved through the Philippines, causing power outages and landslides in several islands. Despite a general warning against small boats sailing, a ferry departed Masbate and capsized due to the storm, killing 28 people. Throughout the country, 41 people died, and damage reached ₱117.57 million. While in the South China Sea, Chanchu caught many Vietnamese fisherman off guard, causing 17 ships to sink and damaging several others. Chinese ships assisted in the search-and-rescue mission, ultimately rescuing 330 fishermen from 22 boats; however, 21 bodies were found, and the remaining 220 missing were presumed killed. In southern China, flooding and strong winds from Chanchu wrecked about 14,000 houses and damaged over of crop fields. Damage was heaviest in Shantou where it moved ashore, with flooding covering roads and entering hundreds of homes. Damage in China totaled ¥7 billion yuan, and there were 23 deaths. Rains from the typhoon killed two people in Taiwan after sweeping them up in a river, and crop damage there reached NT$158.88 million. Later, high waves killed one person in Okinawa and left another person missing, while rains extended into South Korea.
Meteorological history
An area of convection, or thunderstorms, persisted on May 5 southeast of Yap State in the Federated States of Micronesia. Initially it remained disorganized while tracking to the west, although a circulation became more distinct on May 7, indicative of gradual organization. At 06:00 UTC on May 8, the Japan Meteorological Agency declared that a tropical depression had developed about northeast of Palau. Five hours later, the Joint Typhoon Warning Center issued a tropical cyclone formation alert, and at 18:00 UTC they classified the system as Tropical Depression 02W. The system moved to the west-southwest, influenced by the subtropical ridge to the north. Early on May 9, the JTWC upgraded the depression to tropical storm status, and at 12:00 UTC the JMA followed suit by upgrading the system to Tropical Storm Chanchu. Also on that day, the Philippine Atmospheric, Geophysical and Astronomical Services Administration began issuing warnings on the storm as Tropical Storm Caloy.Image:Chanchu 2006-05-12 0030Z.jpg|thumb|right|Severe Tropical Storm Chanchu near Samar on May 11
In its formative stages, Chanchu was located in an environment generally favorable for intensification. Its tracked shifted more to the west-northwest due to a building ridge to the south. Late on May 10, the JTWC upgraded Chanchu to typhoon status, estimating 1 minute sustained winds of. By contrast, the JMA estimated it intensified only into a severe tropical storm with winds of. Turning more to the west, Chanchu made landfall on Samar in the eastern Philippines on May 11. Despite moving through the archipelago, Chanchu intensified slightly within the Sibuyan Sea, striking Mindoro on May 12 with 1 minute winds of, according to the JTWC. On May 13, Chanchu emerged into the South China Sea, and later that day the JMA upgraded it to typhoon status.
Upon reaching the South China Sea, Chanchu encountered an area of warm sea surface temperatures and low wind shear. After an upper-level low to the east provided favorable outflow to the south and the east, Chanchu rapidly intensified on May 14. While the storm was active, the JTWC upgraded Chanchu to a super typhoon with peak 1 minute winds of, although the agency later downgraded the peak winds to. By contrast, the JMA estimated peak 10 minute winds of at 00:00 UTC on May 15. According to the Hong Kong Observatory, the 10 minute winds reached, which made Chanchu the strongest typhoon in the South China Sea in the month of May.
By the time Chanchu attained peak winds, an eastward-moving trough over China broke up the ridge to the north, causing the typhoon to turn sharply to the north into a less favorable environment. With decreased outflow and stronger wind shear, Chanchu began slowly weakening. The eye initially remained small, but the outer eyewall deteriorated on May 16 as the convection decreased in the northern periphery. The trough that previously weakened the ridge steered Chanchu to the north-northeast and forced an extratropical transition. Late on May 17, the JMA downgraded the typhoon to a severe tropical storm. Around that time, Chanchu made landfall near Shantou, Guangdong in southeastern China, about east of Hong Kong; the JTWC estimated landfall winds of, while the JMA estimated them at. Early on May 18, the JTWC discontinued advisories, although the JMA continued tracking Chanchu over southeastern China through eastern Fujian province. Later on May 18, the storm emerged into the East China Sea, becoming fully extratropical at 00:00 UTC on May 19. The remnants continued toward Japan before dissipating at 18:00 UTC that day off the west coast of Kyushu in southern Japan.
Preparations
Officials in southern Leyte recommended that residents evacuate to prevent a repeat of a deadly landslide in February 2006. Officials canceled several flights and ferry lines, stranding 10,000 people. In all, 2,144 people evacuated in the Philippines. PAGASA issued a storm signal number 2 for several provinces along Chanchu's path, as well as storm signal number 1 for other areas, largely forecasting for rainfall and gusty winds.Vietnamese fishermen in the South China Sea received 24 hours of warning from the National Hydrometerological Forecast Center before Chanchu approached the area, less time than other agencies in the region. At one point, Chanchu was forecast to become a strong typhoon and make landfall near Hong Kong. In response to the threat, officials at the Hong Kong Observatory, as well as in Macau, issued a standby signal to inform the public of the approaching typhoon. The HKO issued a warning signal number 3 on May 17. In the territory, 60 flights were canceled with another 14 delayed, beaches were closed, and ferry service was disrupted. Ahead of the storm, about 1 million people evacuated from coastal Guangdong and Fujian provinces to government warehouses, schools, tents, or the houses of relatives. In the former province, 62,000 fishermen were ordered to return to port, while four flights were canceled at Guangzhou Baiyun International Airport. Residents were advised to remain indoors, and workers reinforced billboards in anticipation of the strong winds. Rail and boat transport was stopped between Guangdong and Hainan across the Qiongzhou Strait due to the typhoon. Schools were closed in Guangdong during the storm's passage, although they remained open in Fujian. In Shanghai, the speed limit of Donghai Bridge was halved because of strong winds.
Ahead of the storm, the Central Weather Bureau in Taiwan issued land and sea warnings. The Tainan City Government and three county governments closed for one day. All domestic flights to offshore islands were canceled, and rail service was interrupted. Later, airlines canceled 12 flights in Japan due to the storm.
Impact
The Philippines and Malaysia
While moving through the Philippines, Chanchu affected several islands with strong winds and heavy rainfall. In Legazpi, Albay, strong waves wrecked 100 homes and left 1,500 people homeless. High winds left widespread power outages, particularly in Mindoro, Batangas, and across the Bicol Region. The storm severely damaged the banana industry and affected various other fruit crops. Near Metro Manila, the winds damaged billboards, knocked over trees, and caused isolated power outages. Rough seas sank a ferry off Masbate, despite a warning against the operation of small craft, having left at sunrise to avoid the police. The Coast Guard rescued 18 passengers, but 28 people died in the wreck. An empty ferry sank at port in Tabaco. A ferry with 700 people aboard went missing, but the Coast Guard found it washed ashore with everyone safe on board. Similarly, an oil tanker washed ashore at Pinamalayan, Oriental Mindoro, and its crew of 13 was rescued. Throughout the country, Chanchu killed 41 people, mostly from the Masbate ferry wreck. The storm damaged 5,630 homes, and destroyed 1,013 others, forcing 53,307 people to leave their homes. Agricultural losses totaled ₱71.57 million, chiefly to the corn harvest, with an additional ₱46 million in infrastructure damage.While stalled over the South China Sea, Chanchu's large circulation caused an increase in rainfall over Malaysia. The typhoon brought the onset of the summer monsoon in the South China Sea after shifting the prevailing winds over the region.