By Teachers, For Teachers
What caused Hurricane Sandy?
Violent winds…driving rain… killer waves. These are the hallmarks of a hurricane. Also called cyclones or typhoons, hurricanes are giant storms prowling the world’s tropical seas.
An average hurricane releases as much energy in a day as the explosion of half a million small atomic bombs.
Hurricanes form in the summer and fall, when the sun heats vast stretches of tropical ocean to over 82 degrees. Warm, moist air rises over these hot spots, creating thunderstorms. Upper level winds and surface winds then come together, forming a circular pattern of clouds known as a tropical depression. When the winds exceed 39 miles per hour, a tropical storm has developed. when the winds reach 74 miles per hour, a hurricane is officially born.
Inside the storm, bands of rain up to 300 miles long meet in the eye wall, the most violent section. Here, winds of up to 200 miles per hour spiral upward. Warm, moist air is drawn up from the ocean’s surface, feeding the storm.
Within the center of the hurricane, downdrafts of dry air create a strangely calm area called the eye. fully formed, a hurricane may stretch over 500 miles in diameter… a storm nearly the size of texas… and reach a height of 9 miles.
Most of these storms spin out over the open sea. BUT in an average year, two or three will strike the mainland of North America. When they do, the damage can be catastrophic.
Most dangerous is the storm surge, a wall of water that sweeps across the coastline where a hurricane makes landfall.
About 45,000 people were killed by hurricanes in the 20th century, including some 15,000 in the United States.
hurricanes are also costly in dollars. 1992’s Hurricane Andrew was the most expensive natural disaster in U.S. history, causing more than 25 billion dollars worth of damage.
Scientists are searching for better ways to predict the path of a hurricane. Special planes called “hurricane hunters” fly directly into these monster storms and drop sensors to measure wind speed, temperature and air pressure… providing vital clues to the hurricane’s direction.
New 3-D models are also helping scientists understand this awesome force of nature… and provide quicker and more accurate warnings to anyone unlucky enough to be caught in its path.
video credit: National Geographic