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The shoreline is the contour of wet and dry area where the ocean is in contact with dry land. High and low tides usually alternate along the shoreline with pounding currents of water displaced from the ocean. There are several different types of shorelines namely sandy, rocky and wetlands. The relationship between the ocean and the shoreline plays a vital role in the weather changes occurring along the coastline. Usually, natural disasters occur along the shoreline and in the ocean that are related to weather and climate. Disasters such as hurricanes, tornadoes, tsunamis, floods and many more are affected in one way or another by weather conditions. Some of them are common in the ocean and their effects extend to the shorelines causing massive damages. The objective of this paper is to examine hurricanes as a natural calamity that occurs in the ocean and sometimes extending to the shoreline. A number of questions under this theme will be explained.
What causes the natural event?
Hurricanes are caused by a number of atmospheric conditions. A low atmospheric stability, pre-existing disturbance, moist mid-air and upper air divergence are among these conditions. These are factors that aid in transportation of heat energy from the tropics to higher latitude areas. When tropical waters are heated by the sun up to about 820F, air warms up and rises carrying with it water vapor. The heated air and vaporized water rise faster and faster due to the heat from the sun. The air starts to circle in a counterclockwise motion and form strong whirling winds that continue to gain speed. A combination of a hurricane's surface winds and the physical configuration of the shoreline cause storm surges. The surface winds above the water surface push water towards the center of the hurricane, known as the hurricane eye. This creates a mound of water which is influenced by the slope of the shoreline as it approaches the land. If the coastline is shallow, the hurricane grows and advances towards dry land. If the coastline is deep, the water is dispersed or the mound may grow relatively slowly according to the strength of the hurricane (Walsh, 2008).
Would the effects of this event be any different if it occurred at a high or low tide? If so how?
Weather is mostly influenced by tidal levels and relative position of dry land. Atmospheric circulations elevate oceanic tides. A rise of water generated by a hurricane storm is known as a storm surge and causes immense flooding along the coast. When the storm surge coincides with a high tide, the storm can reach to levels of over twenty feet high. The storm surge is produced when water is pushed to the shore by the whirling wind in the storm. If on low tide, a hurricane has minimal intensity. The impact of the surge under low pressure does not cause an intense storm in the water moving towards the shore. If a hurricane moves to the shore during a low tide, the tidal range is relatively smaller and the storm surge is less immense (Storm Surge Overview, 2010).
How does this event change the wave action of the ocean?
The most notable effects of hurricanes are the creation of enormous ocean waves that are hazardous to anything on land. These storms cause waves to rise as high as thirty feet and can demolish all shoreline structures. They can erode coastlines and even wash away roads along the coastline. Most hurricane waves are complex and move over shorter distances. The height of an ocean wave changes with the speed of a hurricane wind. It is also believed that the overall wave field is also affected by the size and radius of the strongest winds of a hurricane storm (ScienceDaily, 2006). The most fortunate thing is that most massive waves of a hurricane storm are dramatically decreased in size after interaction with the continental shelf of the ocean and other nearby land forms. For example, islands may act as barriers by protecting the mainland and the deep sea. It absorbs the strong waves hence sheltering the mainland.
Which ocean currents (deep and surface) pass near or through the disaster impact area?
Ocean currents are important breeding grounds for hurricanes. Currents that flow on higher latitudes exerts pressure on low latitude areas. Currents that flow towards the poles make mid-latitude waters warm. On the other hand, cold ocean currents reduce the range between high and low latitude areas and they are more likely to cause hurricanes. Warm currents expand this range and therefore are less likely to cause hurricanes. Surface water currents account for about 10% of ocean water. They are found in the upper 400 meters of the ocean water. Conversely, deep water currents account for the rest of ocean water. The currents move in the basin of the ocean and are driven by forces such as gravity. During a hurricane, surface currents pass near the storm and may combine with the circulating currents of the hurricane.
Is the disaster affected by surface or deep ocean currents? If so, how?
Deep currents can make a hurricane to strengthen. They enable it to intensify rapidly into a higher category hurricane. In fact the intensity can continue increasing for as long as the hurricane is active. An example is the Hurricane Camille in 1969. The hurricane formed in deep warm Caribbean waters that made it to intensify to a major hurricane category (category 3). As the hurricane rounded the Cuban west coast, its intensification increased rapidly to reach category 5. The hurricane maintained immensely high winds of over 300 miles per hour. Other hurricanes have been to intensify to hazardous levels as a result of interacting with deep ocean currents.