英语六级阅读备考：快速阅读练习(5)_大学英语阅读

英语六级阅读备考：快速阅读练习(5)

　　The weather systems spin anticlockwise in the northern hemisphere and clockwise in the southern. The rotation of the Earth also determines the direction in which these storms travel, so hurricanes in the north Atlantic move west towards Central and North America.

　　Categorically Speaking

　　As winds increase to a sustained speed of 63 kilometers per hour, a tropical depression becomes a tropical storm. Such storms are then given a namesuch as Charley, Frances, Gilbert, Isabel, Ivan Jeanne or Mitchwhich cycle through the alphabet each year.

　　A tropical storm becomes a category 1 hurricane when winds reach sustained speeds of 120 kph. A hurricane becomes category 2 when sustained winds hit 154 kph, category 3 at 179 kph, category 4 at 210 kph, and finally the most devastating variety, category 5, when wind speeds hit 250 kph.

　　Category 5 hurricanes rarely make it to land2005s Katrina briefly achieved category 5 status, but diminished slightly before landfall.

　　Hurricanes are characterized by high winds, torrential rain and sometimes tornadoes. These conditions cause massive damage to buildings and infrastructure and create flash floods, mudslides and storm surges of sea water. Storm surges are huge tsunami-like waves resulting from the acutely low pressure at the eye of the hurricane. The low pressure draws in water, raising sea levels by up to 4 meters, Hurricanes may even trigger weak earthquakes and set the Earth vibrating.