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Typhoon Chaba was the strongest tropical cyclone in the western Pacific during 2004 and caused a swath of damage from the Mariana Islands to Japan from August through September of that year. Chaba was the Japan's second costliest storm during the season, only behind Songda in September, and peaked as a typhoon with maximum sustained winds equivalent to that of a Category 5 on the Saffir–Simpson hurricane wind scale. Chaba originated from a gradually developing area of disturbed weather on August 18, northeast of Kwajalein. Tracking westward, the system gained tropical storm strength the following day and then reached typhoon intensity on August 20. Rapid intensification ensued thereafter, with Chaba quickly attaining its peak intensity on August 23 as it began to curve towards the northeast. This intensity was maintained for several hours before the typhoon began to fluctuate in strength as it began to meander south of Japan beginning on August 26. Three days later, Chaba made landfall on Kyushu, later tracking across the Sea of Japan as it concurrently weakened. On August 31, the storm transitioned into an extratropical cyclone, and later dissipated in the Sea of Okhotsk on September 5. The typhoon caused significant damage to areas of the Northern Mariana Islands, which were buffeted by strong typhoon-force winds. Rota was worst affected by Chaba, as the island remained under the storm's eyewall for several hours. Gusts peaked at 219 km/h (136 mph) at Rota International Airport, and the strong winds damaged and destroyed a multitude of homes. Power outages were frequent across the commonwealth, and beach erosion resulted from strong storm surge. Damage in the Northern Mariana Islands amounted to US$18 million, and 13 people were injured, with one fatality. Another fatality occurred in Guam under similar circumstances, though the island sustained less damage. Following the storm, a state of emergency was declared in Guam and areas of the Northern Mariana Islands were declared federal disaster areas. Most of the damage caused by Chaba occurred in Japan, where 18 people were killed and damage figures reached JP¥105.4 billion (US$959 million). The typhoon remains the country's fourteenth costliest on record. A total of 8,627 homes were destroyed by the storm's effects, with another 46,561 inundated by floodwater. Impacts in Japan were primarily concentrated on Kyushu, where Chaba made its first landfall. Rainfall peaked at 821 mm (32.32 in) in Miyazaki Prefecture. Like in the Northern Mariana Islands, power outages and transportation delays were of numerous extent in Japan. ==Meteorological history== Typhoon Chaba stemmed from an area of disturbed weather that quickly developed northeast of Kwajalein on August 18. Within an area of favorable atmospheric conditions, the system became sufficiently organized to be classified as a tropical depression by the Japan Meteorological Agency (JMA) at 0600 UTC that day. Tracking westward under the influence of a nearby ridge,〔 strengthening continued and the storm reached tropical storm intensity at 1200 UTC on August 19. It was at this time that the system was assigned the name ''Chaba''.〔 Strengthening at a climatologically normal pace, Chaba reached severe tropical storm intensity at 0000 UTC on August 20.〔 However, over the day's course, analysis of wind patterns about the cyclone indicated that Chaba's upper-level circulation was decoupled from its surface circulation. Nonetheless, this period of deorganization was limited, and the tropical storm began to quicken in intensification. Early on August 21, microwave imagery showed that Chaba had developed a large cloud-filled eye, signifying additional strengthening.〔 At 1800 UTC on August 20, the JMA upgraded Chaba to typhoon status,〔 while the system was roughly 345 km (215 mi) east-southeast of Saipan.〔 Much of the rapid intensification pattern was attributed to the development of dual outflow channels during the day's course. Concurrently Chaba began to curve towards the northwest around the periphery of the nearby, dominant subtropical ridge in response to an approaching longwave,〔 sweeping past the Mariana Islands.〔 At 1800 UTC on August 23, the JMA assessed the typhoon to have reached its peak intensity with maximum sustained winds of 205 km/h (125 mph) and a minimum barometric pressure of 910 mbar (hPa; 26.87 inHg).〔 An intense albeit average-sized typhoon, Chaba held this intensity for two days before dry air began to impact the cyclone. On August 26, the typhoon's convection slightly weakened, and the more intense convective activity became limited to the southern and eastern sides of the system.〔 On August 27, the longwave trough that had in part steered Chaba northward moved out of the region,〔 and after slowing down, the typhoon began to assume a westerly course. Chaba initiated a eyewall replacement cycle the next day, further weakening the system. A second longwave trough propelled Chaba towards the north-northeast,〔 bringing it to a landfall near Kushikino, Kagoshima at 0000 UTC on August 30,〔 with sustained winds of 150 km/h (90 mph).〔 Chaba quickly crossed Kyushu and briefly emerged over water before making a second landfall on Hōfu, Yamaguchi.〔 At 1200 UTC on August 30, the JMA downgraded from typhoon status to severe tropical storm status,〔 and six hours later, Chaba entered the Sea of Japan. Racing towards the northeast, the storm made its final landfall as a tropical system near Oshamambe, Hokkaido on August 31 shortly before transitioning into an extratropical cyclone. These remnants persisted for several days, tracking across the Sea of Okhotsk and moving towards the coast of Russia.〔〔 On September 4, the extratropical cyclone became quasi-stationary near Sakhalin before fully dissipating by 1800 UTC the following day.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Typhoon Chaba (2004)」の詳細全文を読む スポンサード リンク
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