Running head: WEATHER ANOMALIES1Weather AnomaliesEarth Science with LabColorado State University – Global CampusMay 31, 2017
WEATHER ANOMALIES 2Weather AnomaliesWeather is a phenomenon that we all live with, whether it be dry conditions, rain, hail, sleet, snow, tornados or hurricanes. Some weather can be mild and some can be severe. This essay will focus on hurricanes as well as the other forms of severe weather that can be triggered by hurricanes such as tornados and flooding. Mentioned below will be information pertaining to what causes hurricanes and the other severe weather that can follow and will mention one or two specific hurricanes that have hit the United States of America as well as some of the damages they have caused and how people can prepare for hurricanes. We will address why we name tropical storms and hurricanes.What causes Hurricanes?Hurricanes, otherwise known as tropical cyclones, are not caused by cool and warm fronts colliding. Instead they are formed by areas of low pressure over the ocean or other body ofwater. Warm, moist air rises above the surface of the ocean, leaving less air beneath. Higher pressure air then pushes below the warm, moist air and into the low-pressure area. The new air then becomes warm, moist air as well and starts to rise. As the cycle continues in the same manner, a swirling pattern starts to form and wind speed increases. As the warm, moist air rises and cools, clouds form and grow. The whole system continues to spin and grow, fed by the warmocean air and evaporation. In the northern hemisphere, the rotation of hurricanes is counter-clockwise. As the storm rotates faster and faster, winds pick up an eye starts to form in the centerof the storm. The eye of the storm is a low-pressure area that is calm and clear, while the surrounding masses of clouds are turbulent and violent. High-pressure air flows from above the spinning cyclone down in through the eye, while warm, moist air continues spinning upward. The picture below shows the cycle of the air flow when a low-pressure system forms.
WEATHER ANOMALIES 3When areas of low-pressure form, they start out as tropical depressions, with winds below 39 miles per hour. When the wind speeds are 39 to 73 miles per hour, the storm becomes atropical storm. When wind speeds climb to 74 miles per hour, the storm becomes a hurricane. The chart below shows the wind speeds, storm surge and probable damage for each category of tropical cyclones. Saffir-Simpson Hurricane ScaleCategoryWind Speed (mph)Storm Surge (feet)Damage5156> 18Catastrophic4131-15513-18Extreme3111-1309-12Extensive296-1106-8Moderate174-954-5MinimalTropical Storm39-730-3Tropical Depression0-380Scientists believe that El Nino has some effect on hurricanes and frequency of them. La Nina is a phenomenon that cools the ocean surface temperatures in the eastern Pacific Ocean near the equator. El Nino is the opposite as it warms the ocean surface temperatures to above
WEATHER ANOMALIES 4average in the eastern Pacific Ocean near the equator. Scientists believe that El Nino causes more