Hurricane season in the Atlantic begins when the temperature of the ocean reaches 26 degrees Celsius. At this point 180 tons of water evaporates every hour. Drawn high into the atmosphere – the rest is history.
Hurricanes, Typhoons, and Cyclones
A tropical cyclone, variably known as a hurricane, typhoon, or cyclone, is a huge rotating air mass, typically having very low pressure, high winds, and torrential rains. Tropical cyclones are the largest storm systems on Earth.
Air always moves from areas of high pressure towards areas of low pressure. The speed of the airflow increases as the pressure difference between the two air cells increases and their proximity decreases.
Hurricanes begin as low-pressure cells that break off from the equatorial low-pressure belt. They begin to spin due to the Coriolis effect and pick up large amounts of water vapor and heat energy as they pass over the warm tropical water. When wind velocity within the storms reaches 120 kilometers (77 miles) per hour, tropical storms are upgraded to hurricane status. In large hurricanes, wind speeds have reached 400 kilometers (250 miles) per hour.
Hurricanes form only in the late summer and fall, when water temperatures reach at least 26 degrees Celsius (79 degrees Fahrenheit). They travel with the trade winds flowing east to west. Most hurricanes last 5 to 10 days and remain in the tropical region. Some storms, however, pass into the middle latitudes where they can cause great destruction along the east and west coasts of the Americas.