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Severe Tropical Cyclone Pam of 2015 was the most intense tropical cyclone in the southern hemisphere in 2015 and regarded as one of the worst natural disasters in the history of Vanuatu. A total of 15–16 people lost their lives either directly or indirectly as a result of Pam with many others injured. The storm's impacts were also felt, albeit to a lesser extent, to other islands in the South Pacific, most notably the Solomon Islands, Tuvalu, and New Zealand. Pam is the second most intense storm of the South Pacific Ocean according to pressure, after Zoe of 2002; Pam is also the third most intense storm in the Southern Hemisphere by the same metric, only after Zoe of 2002 and Gafilo in 2004. In addition, Pam had the highest 10-minute sustained wind speed of any South Pacific tropical cyclone; it is tied with Cyclone Orson and Cyclone Monica for having the strongest winds of any cyclone in the Southern Hemisphere. The Christian Children's Fund of Canada reported that wind gusts reached as high as 320 km/h, and thousands of homes, schools and buildings were damaged or destroyed, with an estimated 3,300 people displaced as a result. Pam formed on March 6 east of the Solomon Islands and tracked slowly in a generally southward direction, slowly intensifying as it did so. Two days later, the disturbance reached tropical cyclone intensity and, over subsequent days, Pam gradually strengthened before reaching Category 5 cyclone status on both the Australian and Saffir–Simpson scales on March 12. The next day, Pam's sustained winds peaked at 250 km/h (155 mph) as the storm moved through Vanuatu, passing near several constituent islands and making direct hits on others. On March 14, Pam's winds began to slowly weaken, but its pressure dropped further to a minimum of 896 mbar (hPa; 26.46 inHg) before rising shortly afterwards. Over the next few days, the cyclone's weakening accelerated as it moved poleward. On March 15, Pam passed northeast of New Zealand before transitioning into an extratropical cyclone that same day. Early in Pam's history, a damaging storm surge was felt in Tuvalu, forcing a state of emergency declaration after 45 percent of the nation's residents were displaced. Torrential rainfall occurred in the southeastern Solomon Islands, particularly in the Santa Cruz Islands. In Vanuatu, all emergency centers were activated and relief personnel were put on standby with Pam assessed as having the potential to be one of the nation's worst tropical cyclones. Catastrophic damage occurred as the storm moved through the archipelago, particularly in Efate, location of the Ni-Vanuatu capital of Port Vila; and the Tafea islands of Erromango and Tanna. The cyclone crippled Vanuatu's infrastructure: an estimated 90 percent of the nation's buildings were impacted by the storm's effects, telecommunications were paralyzed, and water shortages continue to plague the small nation. Pam later brought heavy winds and rough surf to New Zealand's North Island during its weakening stages. ==Meteorological history== On March 6, 2015, the Fiji Meteorological Service (FMS) reported that Tropical Disturbance 11F had developed about to the northwest of Nadi, Fiji. The system was located underneath an upper level ridge of high pressure and within an area favourable for further development with low-moderate vertical windshear.〔 As a result, weather forecast models anticipated the development of a significant tropical cyclone over the coming days.〔 Initially, the disturbance floundered east of the Solomon Islands and slowly strengthened, reaching tropical depression intensity on March 8. The storm's appearance and areal coverage of showers remained stationary until the following day, when the formation of rainbands wrapping about the centre of the system prompted the FMS to upgrade the storm's classification to a category 1 tropical cyclone on the Australian tropical cyclone scale, assigning it the name ''Pam''. Atmospheric conditions at the time were slightly favorable for continued development as the storm continued to slowly track along the southern periphery of a high-pressure area to its north. Following the storm's naming, Pam began to curve southwards around midday on March 9. Computer models continued to point towards the possibility of rapid intensification occurring as the cyclone approached Vanuatu. Significant development in Pam's organization took place throughout the remainder of the day into March 10. The cyclone's circulation centre quickly tightened, with the central dense overcast atop it persisting in strength. At 18:00 UTC on March 10, the FMS upgraded the system to category 3 strength, making it a severe tropical cyclone. Shortly after, microwave imagery revealed a primordial eye-feature developing within Pam; this became apparent on visible light images on March 11. That day, Pam became quasi-stationary east of the Santa Cruz Islands before resuming its prior southwesterly motion towards the end of March 11. The storm's eye continued to warm as its cloud tops cooled such that at 12:00 UTC, the FMS assessed Pam to have reached Category 5 intensity on the Australian cyclone scale. Six hours later, the JTWC estimated that the storm reached Category 5-equivalent intensity on the Saffir–Simpson hurricane wind scale as Pam was east of Penama. Early on March 13, the JTWC determined Pam reached its peak one-minute sustained winds of 270 km/h (165 mph) as it neared Vanuatu. Several hours later, the cyclone began to curve towards the south-southeast, allowing Pam to pass just east of Efate. At that time, the FMS estimated Pam as having record-breaking 250 km/h (155 mph) ten-minute sustained winds. The storm's winds gradually slowed afterwards as Pam tracked west of Tafea. However, the FMS indicated that the cyclone's pressure dropped further to a minimum of 896 mbar (hPa; 26.46 inHg) on March 14, making Pam the second most intense tropical cyclone in the South Pacific basin after Cyclone Zoe in 2002. This intensity was short-lived, however, as Pam's central pressure began rising shortly thereafter as the storm accelerated southeastward. After 12:00 UTC that day, Pam left the area of responsibility of the FMS and entered the monitoring region of New Zealand's Wellington Tropical Cyclone Centre (TCWC Wellington), who estimated that Pam weakened to Category 4 intensity on March 15 after maintaining Category 5 intensity for 36 hours. Shortly after, the storm's eye faded away and Pam's low level circulation became displaced from its associated thunderstorms, signalling a rapid weakening phase. Later on March 15, both agencies discontinued issuing advisories as Pam entered a phase of extratropical transition while affecting northeastern New Zealand. The system moved eastwards, and eventually dissipated over the waters of the South Pacific on March 22. 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「Cyclone Pam」の詳細全文を読む スポンサード リンク
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