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Hurricane Igor was the most destructive tropical cyclone to strike the Canadian island of Newfoundland on record. Igor originated from a broad area of low pressure that moved off the west coast of Africa on September 6, 2010. Tracking slowly westward, it developed into a tropical depression on September 8 and strengthened into tropical storm shortly thereafter. Higher wind shear temporarily halted intensification over the following days. On September 12, explosive intensification took place, and Igor reached Category 4 status on the Saffir–Simpson Hurricane Wind Scale. By this time, Igor had already begun a prolonged turn around the western periphery of the subtropical ridge. Peaking with winds of 155 mph (250 km/h), the cyclone began to enter an area unfavorable for continued strengthening, and Igor gradually weakened before brushing Bermuda as a minimal hurricane on September 20. After turning northeastward, the system began an extratropical transition, which it completed shortly after striking southern Newfoundland. The remnants of Igor were later absorbed by another extratropical cyclone over the Labrador Sea on September 23. While over the open ocean, large swells produced by the hurricane caused the deaths of three people — two in the Caribbean and one in the United States. Passing west of Bermuda as a minimal hurricane, damage was limited primarily to trees and power lines, with roughly 27,500 residences having lost electricity. Total losses in the territory were less than $500,000 (2010 USD). In Newfoundland, damage wrought by Igor was extreme, claimed to be the worst ever seen in some areas. Large stretches of roadways were completely washed out by severe flooding, including a portion of the Trans-Canada Highway, isolating approximately 150 communities. Throughout the region, one person was killed and damage costs amounted to a record $200 million (2010 CAD). In the storm's wake, military personnel were deployed to assist in recovery efforts and aid distribution. ==Meteorological history== Hurricane Igor was first identified as a broad area of low pressure accompanying a tropical wave over western Africa in early September 2010. Tracking nearly due west, the system emerged into the eastern Atlantic Ocean on September 6. Gradual development took place as convection – thunderstorm activity – consolidated around its center. At 0600 UTC on September 8, the low was deemed sufficiently organized to be classified as a tropical depression while situated roughly 90 mi (140 km) southeast of the Cape Verde Islands. Attaining gale-force winds six hours later, the depression intensified into a tropical storm and was subsequently named ''Igor'' by the National Hurricane Center (NHC). Development of Igor quickly ceased once it was named as a nearby disturbance produced moderate wind shear over the storm, displacing convection from its center. Embedded within a monsoon trough over the eastern Atlantic, the system maintained a slow westward track as it weakened to a tropical depression on September 9. Intensification resumed the following day once shear lessened and the dominant steering factor shifted to a mid-tropospheric ridge north of Igor; it would remain so throughout the remainder of the cyclone's existence. Contrary to its earlier movement, the storm's forward motion markedly increased.〔 Following the development of an intermittent eye feature and steady convection around its center, Igor strengthened into a hurricane around 0000 UTC on September 12.〔 Once classified a hurricane, Igor underwent explosive intensification over the following 24 hours. During this time, satellite observations indicated that the storm's winds increased from 75 mph (120 km/h) to 150 mph (240 km/h) and its barometric pressure decreased by 52 mbar (hPa; 1.53 inHg).〔 Near the end of this phase, forecasters at the NHC predicted that Igor would attain Category 5 status, the highest classification on the Saffir–Simpson Hurricane Wind Scale. With a symmetrical 17 mi (27 km) wide eye, deep convection and spiral banding, Igor maintained Category 4 intensity for nearly five days. Minor fluctuations took place during this period as multiple eyewall replacement cycles occurred. After the first of these cycles, the hurricane is estimated to have reached its peak strength around 0000 UTC on September 15 with winds of 155 mph (250 km/h) and an estimated pressure of 924 mbar (hPa; 27.29 inHg). By this time, Igor began a northwestward track as it executed a prolonged "C-shaped" curve over the Atlantic Ocean.〔 Passing roughly 345 mi (555 km) northeast of the Leeward Islands on September 17, Igor gradually weakened as it experienced increased wind shear and dry air intrusion. Over the following several days, the storm became exceedingly large,〔 with tropical storm-force winds covering an area about 920 mi (1,480 km) wide. Due to an overestimated bias in Igor's intensity, forecasts from the NHC showed that the storm would strike Bermuda as a major hurricane. However, weakening was more marked than anticipated and by the time its center neared the territory on September 20, winds decreased to 75 mph (120 km/h). Igor made its closest approach to Bermuda around 0230 UTC, passing roughly 40 mi (65 km) to the west-northwest.〔 Once north of Bermuda, Igor began to undergo an extratropical transition as it turned northeastward. Though deep convection was no longer consistently over its center, data from Hurricane Hunters continued to support hurricane intensity. Accelerating along the leading edge of a trough over the Canadian Maritimes, the storm intensified within a baroclinic zone as it neared Newfoundland.〔 The interaction between these two systems allowed the hurricane to strengthen despite moving over decreasing sea surface temperatures.〔 Around 1500 UTC on September 21, Igor made landfall near Cape Race, with winds of 85 mph (140 km/h), slightly higher than several hours earlier. Shortly thereafter, the storm completed its transition into an extratropical cyclone as it became fully embedded within the baroclinic zone. After turning northwestward between Labrador and Greenland, the remnants of Igor were absorbed by another extratropical cyclone on September 23.〔 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「Hurricane Igor」の詳細全文を読む スポンサード リンク
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