Introduction
What is a hurricane? “Hurricane” is a word that was corrupted from the word “Huracan” which was traditional Taino name for an evil god. Hurricanes are also known by other names depending on where one is: typhoons, or cyclones, or baguios are some of the names that are used. They are also referred as the world’s greatest storms sometimes having the power of ten thousand nuclear bombs and thus are rated as natural hazards of great magnitude that affect both people and the environment (Fitzpatrick, 1999).
Main body
A hurricane can be classified as a gigantic tropical storm with a width of up to 600 miles. Hurricanes usually take place in summer or in autumn and gather in open oceans and are characterized by winds of at least 63Km/h.Hurricanes are mainly restricted to the Northern Atlantic Ocean (Elsner et al, 1999).
It is important at this stage to draw the difference between a hurricane and a tropical storm. Most people at times use both terms to refer to the same thing. However tropical storms are of less intensity and precede the actual hurricane (NOAA).
Hurricanes basically evolve in three stages namely:
- Tropical depression
- Tropical storm
- Hurricane
Tropical depression occurs when a group of storms converge under some conducive atmospheric conditions for a prolonged period of time. Once this has intensified to a point where the maximum wind velocity reaches about 39-73mph, it transforms into a tropical storm. The storm assumes a more circular shape. It then becomes a hurricane when wind speeds reach about 74mph sustainable speeds (NOAA).
A Saffir-Simpson scale is an instrument used to measure the category of a hurricane. The Saffi-Simpson scale is a device that is used to classify the relative strength of hurricanes. The classification is done by approximating the hurricanes’ winds and storm’s relative damage of the coastline where it hits. Therefore the scale basically measures the intensity of the storm. The scale is usually calibrated from 1 to 5, and the readings are normally determined by the wind speeds. Meteorologists use the scale to assess the level of damage at the coast line after a hurricane episode (Fitzpatrick, 1999).
A storm surge happens when a hurricane moves water up; the next event is water landfall resulting to a storm surge. Storm surges therefore are basically onshore floods of water which are usually associated with low pressure and intense weather system which can be classified typically as a tropical cyclone. It occurs as a result of an elevated sea surface which emerges from a reduced atmospheric pressure around the sea. Also, the storm winds that drive the sea water into the coast line can lead to the formation of storm surges which are quite big and sometime exceed six meters (Richard & Kam-biu, 2004).
Hurricanes’ records for the year 2005 running to 2007 are very different and do not show some consistency according to the various records by NASA; for example during the year 2005, the number of hurricanes rose to 15 above the normal average, this was the highest number of hurricanes to have ever been recorded in history, Tropical depressions were 25 which progressed to 22 tropical storms and later to 15 hurricanes. However, in 2006 the records show that there were only 5 number of hurricanes with 13-16 tropical storms (NASA, 2006), the number rose slightly to 6 in 2007.The vast difference between the years 2005 to 2007 was attributed to dust and dry air (NASA, 2006). Various data analyzed for the last 100 years have shown a marked increase in the number of hurricanes which show some very close correlation with sea surface temperatures. Most of the meteorologists attribute this rise to the global warming that is evident across the world due to human activity.
There are other weather related processes which can adversely affect hurricanes seasons. These include: Heavy rainfall which results to flooding and strong wind which result to destruction of properties. When heavy rainfall coincides with hurricanes, the degree of damage is quite high since it causes flooding which eventually leads to the loss of life and property. The rise in pressure at the sea level can also affect hurricane seasons (NOAA).
Conclusion
Global warming has been variably described as the major contributing factor to the increased cases of hurricanes for the last one century. Human activity such as the release of green house gases has had a significant effect. Unfortunately in many instances the hurricanes cause so much human damage especially to the vulnerable, for example Hurricane Katrina led to the great suffering of the general population in New Orleans. However, the great technological advancements even though unable to conclusively predict when and where the storms will hit, are able to detect the moment a storm builds up, the cause and the likely route the storm might take. This helps greatly in disaster prediction and mitigation and evacuation measures even days before the storm hits home.
References
- Elsner, James B., and A. Birol Kara.(1999): Hurricanes of the North Atlantic: climate and society. New York, Oxford University Press.
- Fitzpatrick, Patrick J. (1999) Natural disasters, hurricanes: a reference handbook. Santa Barbara, CA, ABC-CLIO,
- NASA, (2007), 2006 “Hurricane Season.” Science Daily. Web.
- National Oceanic and Atmospheric Administration (NOAA): Hurricanes.
- Richard J. Murnane and Kam-biu Liu (Ed) (2004): Hurricanes and typhoons: past, present, and future. New York, Columbia University Press.