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Hurricane Erika was the strongest and longest-lasting tropical cyclone in the 1997 Atlantic hurricane season. It developed from a tropical wave on September 3 and moved west-northwestward across the tropical Atlantic Ocean, steadily intensifying until it attained hurricane status on September 4, becoming the fifth named storm and third hurricane of the season. Erika passed a short distance to the north of the Lesser Antilles, and later turned to the north in response to an approaching trough. The hurricane quickly strengthened to become the only major hurricane of the season, reaching maximum sustained winds of 125 mph (205 km/h) on September 8; after maintaining its peak strength for 24 hours, Erika began to weaken as it passed over cooler waters. It turned to the east, weakened to a tropical storm, and became extratropical after passing near the Azores archipelago. The hurricane produced light rainfall and winds throughout the northern Lesser Antilles. The passage of Erika carried a cloud of volcanic ash to Antigua from the eruption of the Soufrière Hills Volcano on Montserrat, a rare occurrence. Strong waves from the hurricane produced beach erosion and coastal flooding in northern Puerto Rico, and caused the death of two surfers. Moderate wind gusts in the northern Leeward Islands and Puerto Rico left thousands of residents without power, and resulted in $10 million (1997 USD, $12.6 million 2006 USD) in damage in the U.S. Caribbean territories. Erika also produced gusty winds and light rain in the Azores. Erika was the only tropical cyclone in the Atlantic Ocean in the months of August and September, the first occurrence of such event in an Atlantic hurricane season since 1929. ==Meteorological history== A large tropical wave, which eventually became Erika, moved off the coast of Africa on August 31. Shortly after leaving the coast, it displayed a large low-level circulation, though as it tracked westward, the circulation failed to contract significantly. It slowly organized, and by September 3 the convection within the circulation had sufficiently organized for the system to be classified as Tropical Depression Six, while located about 1150 miles (1850 km) east of the southernmost Lesser Antilles. The depression moved west-northwestward at approximately 20 mph (32 km/h) under the influence of a well-established subtropical ridge, and late on September 3 the system intensified into a tropical storm. At that time, the National Hurricane Center in Miami gave the storm the name of ''Erika''. Erika continued to the west-northwest, and in the early hours of September 4, an eye-like feature appeared to have developed in the center of the deep convection. The feature was not an eye, though, as visible satellite imagery revealed a center partially exposed from the convection. Despite unfavorable wind shear, Erika strengthened further and intensified into a hurricane late on September 4, while located 530 miles (850 km) east-southeast of Guadeloupe. Deep convection re-developed near the center, and the hurricane slowly strengthened as it continued west-northwestward. Hurricane Erika decelerated its forward motion as it approached the Lesser Antilles, and passed within 85 miles (135 km) of the islands as a Category 1 hurricane. An approaching trough weakened the subtropical ridge, resulting in Erika turning to the north and later to the northeast. On September 7, Erika began to quickly intensify, and the hurricane reached its peak strength of 125 mph (205 km/h) on September 8, while located about 350 miles (565 km) north of the Lesser Antilles. Erika maintained peak intensity for about 24 hours before weakening over cooler waters.〔 After passing about 350 miles (565 km) east of Bermuda on September 10, Erika turned to the east-northeast in response to westerly steering currents. Increased upper-level wind shear weakened the hurricane to a tropical storm on September 12. Erika continued to weaken as it turned to the east-southeast, though it maintained deep convection near the center despite unfavorable atmospheric conditions. On September 14 the storm turned to the northeast again, and re-strengthened to reach winds of while located 510 miles (820 km) west-southwest of the Azores. On September 15 Erika passed near the western Azores islands, and quickly weakened as deep convection diminished. Erika became an extratropical cyclone on September 16 north of the Azores, and after executing a clockwise loop, the extratropical storm dissipated on September 19 about 230 miles (370 km) southwest of Ireland.〔 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 Erika (1997)」の詳細全文を読む スポンサード リンク
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