ABOUT HURRICANES
Hurricanes are giant, spiraling tropical storms that can pack wind speeds of over 160 miles (257 kilometers) an hour and unleash more than 2.4 trillion gallons (9 trillion liters) of rain a day. These same tropical storms are known as cyclones in the northern Indian Ocean and Bay of Bengal, and as typhoons in the western Pacific Ocean. The Atlantic Ocean’s hurricane season peaks from mid-August to late October and averages five to six hurricanes per year. Centuries ago, the Spanish used huracan, an indigenous word for evil spirits and weather gods, to name the storms that sank their ships in the Caribbean. Today "hurricane" is one of three names for a rotating tropical storm with winds of at least 74 miles (119 kilometers) an hour. These storms are called hurricanes when they develop over the Atlantic or eastern Pacific Oceans. They are cyclones when they form over the Bay of Bengal and the northern Indian Ocean, and they are typhoons when they develop in the western Pacific. Whatever their names, these storms are capable of annihilating coastal areas and causing massive death tolls. HOW ARE HURRICANES FORMED? Hurricanes begin as tropical disturbances in warm ocean waters with surface temperatures of at least 80 degrees Fahrenheit (26.5 degrees Celsius). These low pressure systems are fed by energy from the warm seas. If a storm achieves wind speeds of 38 miles (61 kilometers) an hour, it becomes known as a tropical depression. A tropical depression becomes a tropical storm–and is given a name–when its sustained wind speeds top 39 miles (63 kilometers) an hour. When a storm’s sustained wind speeds reach 74 miles (119 kilometers) an hour it becomes a hurricane and earns a category rating of 1 to 5 on the Saffir-Simpson scale. Hurricanes are enormous heat engines that generate energy on a staggering scale. They draw heat from warm, moist ocean air and release it through condensation of water vapor in thunderstorms. Hurricanes spin around a low-pressure center known as the “eye.” Sinking air makes this 20- to 30-mile-wide (32- to 48-kilometer-wide) area notoriously calm. But the eye is surrounded by a circular “eye wall” that hosts the storm’s strongest winds and rain. A DAMAGING STORM These storms bring destruction ashore in many different ways. When a hurricane makes landfall, it often produces a devastating storm surge that can reach 20 feet (6 meters) high and extend nearly 100 miles (161 kilometers). Ninety percent of all hurricane deaths result from storm surges. A hurricane’s high winds are also destructive and may spawn tornadoes. Torrential rains cause further damage by spawning floods and landslides, which may occur many miles inland. The best defense against a hurricane is an accurate forecast that gives people time to get out of its way. The National Hurricane Center issues hurricane watches for storms that may endanger communities, and hurricane warnings for storms that will make landfall within 24 hours. Hurricane Safety Tips BEFORE IT HITS • Coastal residents should form evacuation plans before a warning is issued to identify a safe shelter and a route to get there. • Prepare for a hurricane by stocking up on emergency supplies including food, water, protective clothing, medications, batteries, flashlights, important documents, road maps, and a full tank of gasoline. DURING THE STORM • As a storm unfolds, evacuees should listen to local authorities on radio or television. Evacuation routes often close as a storm develops. Dedicated professionals and improved technology have made hurricane forecasting more accurate than ever before—but it’s far from precise. • If forced to weather a storm, get inside the most secure building possible and stay away from windows. • Remember that a lull often signifies the storm’s eye—not its end. Anyone riding out a hurricane should wait for authorities to announce that the danger has passed. Comments are closed.
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Erik E. Mason
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