Hurricanes are characterized by a low-pressure core that generates thunderstorms. The strong winds and heavy rain associated with the phenomenon, result in destruction of habitat. This display of nature's fury is a major atmospheric circulation mechanism.
Tropical cyclones are also referred to as hurricanes. They are formed when heat is released as moist air rises, during evaporation. The resultant; condensation of water vapor, fuels the formation of cyclonic windstorms and polar lows. This phenomenon leads to the formation of a warm-core storm system.
Hurricanes are commonly observed along the equator doldrums and tropical regions of the planet. The counterclockwise rotation observed in the Northern Hemisphere and clockwise rotation of winds recorded in the Southern Hemisphere, differ in strength according to location and surge.
Hurricane Formation and Characteristics
Hurricanes are also called typhoons, cyclonic storms and tropical depressions. They are characterized by powerful winds, torrential rain, formation of high waves and tornadoes. Most hurricanes develop over large water bodies, and gradually fade out as they move inland.
This is the main reason behind the coastal regions facing a lot of damage to life and property, in comparison to the inland regions. Hurricanes generate inland flooding, and storm surges up to 40 kilometers!
The movement of warm air, within the hurricane, from the tropics to the temperate latitudes, makes them a major air circulation mechanism. The other advantages of hurricanes include their role in relieving drought and maintaining the troposphere's equilibrium.
Tropical hurricanes have a core of 'sinking' air, also referred to as the 'eye of the hurricane'. Interestingly, the weather in this core region is calm and cloud free. The spherical formation may range in size from 2.5 kms to 370 kms in diameter! The 'stadium effect' refers to the outward curving of the eye-wall, to resemble a stadium.
The hurricane also has a CDO or Central Dense Overcast. This region is the concentrated thunderstorm bearing region near the center or eye of the hurricane. The size of a hurricane is usually determined on the basis of the measurement from the 'center of circulation' to the outermost 'isobar'.
The primary energy source within the formation is the heat released during the process of evaporation and physical forces such as the Earth's gravity and rotation.
Interesting Facts about Hurricanes
The intensity of a hurricane is measured on the Saffir-Simpson Scale. Based on these readings, a hurricane is ranked with a number between 1 and 5. With 5 considered to be a catastrophic hurricane, possessing winds over 155 mph.
The words hurricane, cyclone and typhoon are all different names given to the same type of storm. The name indicates the geographical location of the storm.
Storms over the North Atlantic or the Caribbean are termed as hurricanes. Storms occurring in the western Pacific Ocean, are known as typhoons. Whereas storms or hurricanes forming over the Indian Ocean are termed as cyclones.
In the 19th century an Australian weatherman named Clement Wragge, came up with the idea of naming hurricanes. Since then all hurricane names were women's names. In 1979, men's names were added to the list.
Unless the storm is particularly destructive, the storm names are reused from year to year. Following the massive damage it inflicted in Louisiana and Mississippi in 2005, the name Katrina was retired from hurricane names list.
A hurricane rotates anti-clockwise around its eye and the eye can be up to 20 miles wide. The outer diameter of the hurricane can be as wide as 400-500 miles. An interesting feature is that the weather in the eye is misleading and is surprisingly calm where one can witness clear blue skies too.
A hurricane can dump 6 inches to a foot of rain across a region. The most violent winds and heaviest rains take place in the eye wall and thunderstorms closely surrounding the eye. Hurricane Floyd which struck in 1999 was barely a category I hurricane, but it still destroyed 19 million trees.
Hurricane formation is currently being extensively researched upon. The exact point at which each of the hurricane triggers, spark the onset remains unknown.
A detailed study of the tropical water temperature variations, rapid cooling with altitude, high humidity, low wind shear, and the presence of a previously existent disturbance in weather, is very important to understand the phenomenon.
Tropical hurricanes are associated with shipwrecks, large-scale destruction to life and property, and increased risk of disease propagation.
Hurricane activity is most commonly observed in late summer. This is mainly due to the striking difference between sea temperatures and seasonal basin patterns, within each identified temperature zone.
While May is observed as the least active hurricane month, September is considered the most active, worldwide.
The six Regional Specialized Meteorological Centers worldwide are responsible for tracking hurricanes. These laboratories also issue warnings and advisories about hurricane formations in the designated areas. They function alongside six Tropical Cyclone/Hurricane Warning Centers, that ensure awareness in smaller regions.