Natural Hazards and Disasters : Hurricanes - Essay Example

Category 5 is the deadliest of all. Basically, hurricanes start as a collection of tropics storms over the ocean. Moist air and thermal energy from the ocean surface, high atmospheric pressure atmosphere and convection lifts air is taken through deepening low pressure center. Further, the wind rotation currents tend to spin the clouds into a tight curl. Eventually, a tropical storm is formed from the depression as the wind reaches gale force (Coleman, 2008). Normally, the influence of a mature hurricane extends over an area 805km in diameter and it is nearly circularly symmetrical.

Generally, a cyclone that first passes through two intermediate stages; namely tropical depression and tropical storm before reaching hurricane intensity. As a result of the very low central pressure of about 28.35 in./960 millibars or sometimes lower, with a record 25.69 in./870 millibars registered in a 1979 NW Pacific typhoon surface air spirals inward cyclonically both counterclockwise and clockwise meeting on a circle of about 30 km diameter that surrounds the hurricane's center. Basically, the circumference of this circle defines hurricane’s eye wall, where moisture-laden air is forced upward, causing condensation and the followed by a release of latent heat (Coleman, 2008).

Further, after reaching high altitudes of tens of thousands of feet above the surface, finally, this air is forced out toward the storm's periphery which eventually creates the spiral bands of clouds that can easily be identified in satellite photographs. The upward velocity of the air and subsequent condensation makes the eye wall the region of heaviest precipitation and highest clouds. Because the outward increase in pressure is greatest there, the eye wall is also the region of maximum wind speed.

By contrast, the hurricane eye is almost calm, experiences little or no precipitation, and is often exposed to a clear sky. Temperatures in the eye are 10°F to 15°F (5°C–8°C) warmer than those of the surrounding air as a result of sinking currents at the hurricane's core. Normally, during their early stages hurricanes move westward at about 16 kph and then curve pole ward as they move towards the oceans western boundaries at 20° to 30° latitude. Incipient hurricane in the Northern Hemisphere, usually form over the tropical Atlantic Ocean and mature as they roam westward. 2. Compare Hurricane Katrina (2005) and Hurricane Sandy (2012).

Hurricane Katrina and sandy occurred differently in relation to their paths. Hurricane Katrina was category 3 hurricanes winds between 111-130mph while hurricane Sandy was post-tropical cyclone and classified as category 2. Gulf Coast in 2005 Katrina was deadly and most destructing in this year along the Atlantic. Katrina hit southern Louisiana, Mississippi and Alabama. Sandy occurred in 2012 and caused a lot of destruction and damage too. Furthermore, Sandy developed from waves of the tropical in the western Caribbean Sea.

The storm maximum diameter of Katrina was 415miles while Sandy had a maximum diameter of 1000 miles (Groen, 2010). The duration over land of the two storms was a close range as Katrina took 33hours while Sandy took 32 hours Hurricane Katrina and sandy caused a lot of destruction. Consequently, the hurricanes occurred in a number of states. Sandy affected seventeen states while as Katrina affected sixteen states. Over 100 people died in US from hurricane sandy while 1836 people died from the hurricane Katrina.

Further, the two storms caused