Hurricanes, all have the same basic physical structure. Picture perfect hurricanes or scruffy systems struggling to survive are sparked, formed and developed in the same manner.
Despite their massive strength and size, hurricanes are considered as fragile as they are strong; delineated by only a super-fine line that separates an atmospheric ferocity from a rickety splotch of innocuous clouds and a few drops of rain.
A tropical cyclone is the general description given to hurricanes, tropical storms and tropical depressions. However, for a hurricane to form, there needs to be four essential ingredients:
- Existing thunderstorms
- Warm water
- Moist air
- Light winds
These ingredients receive energy from warm ocean waters; typically where surface temperatures are at least 80°F.
The winds surrounding a hurricane must remain light for this allows the system to morph to its ideal shape. While it is a rarity when these ingredients blend together perfectly, it happens. And when it happens, these destructive weather events make landfall in a most catastrophic way.
Hurricanes are borne from clusters of thunderstorms.. When the air rushes upwards towards the thunderstorm, the pressure at the surface drops suddenly. The air surrounding the lowered pressured area races to the newly created void. This, in turn, creates the counterclockwise rotation necessary to build a closed low-pressure system. Should you wish to research this topic further, follow this link to the Coriolis effect:
Newly developed tropical storms are typically referred to as ‘tropical depressions.’ Tropical depressions are slightly annoying weather events; with wind speeds of no less than 39 miles per hour. They are hardly headline makers, as they look pretty dull when shown through satellite imagery. But tropical depressions can (and do) grow stronger, and some even hit the big-league and become a named hurricane. However, be forewarned, tropical depressions often produce massive amounts of rain.
The thunderstorms will continue to grow stronger if the environment is just right! The internal thunderstorms begin to wrap around the center of circulation, while the wind speeds rise to the range of 39 and 73 MPH.
Tropical storms that gain in strength begin to develop the ‘classic’ hurricane formation. Rain bands are flung out from the center to create spiraling storms around the center. The rain bands bring damaging winds, heavy rain and often an occasional tornado. As the storm continues to strengthen, the rain bands follow suit and begin to intensify.
The strongest thunderstorms surrounding the center eventually mature to create the storm’s eye-wall—the mechanism that creates the necessary power to sustain itself.
The air that is sucked up by these massive thunderstorms must find a place to go. It does, the air is pushed up to high altitudes where it creates an ‘anticyclone’ – a high air-pressure center above the original storm. The best way to describe the purpose of the anticyclone is to compare it to an exhaust pipe, – a conduit that allows the storm to “breathe,” and to remain healthy.
The eye begins to form due to the intricate circulation of air fighting for space between the warm ocean waters below and the thunderstorm’s s apex. In this process, the air warms and dries to create the classic hurricane ‘eye’ – the classic hurricane characteristic easily picked up by satellite imagery. The eye of a hurricane can range from a couple miles to the size of an island.
Ultimately, the eye becomes more defined as the storm strengthens and the danger grows.
The Energy Source
A hurricane’s energy, as noted above, is sourced from tepid ocean waters. But, how does that explain how warm water becomes a life-threatening hurricane? Several theories abound and ruminate through the minds of hurricane experts.
A popular theory suggests that the strong winds created by a hurricane help to energize the storm through a feedback loop. The warm waters feed the storm and increases wind speed. Simultaneously, the increasing winds feed the storm with even more energy from the warm waters below.
Warm ocean waters provide energy to strengthen hurricanes through the concept of latent heat release. While often considered a tough concept to grasp, the easiest way to describe the release of latent heat is as follows:
Think of a really, really hot day. When seeking relief from the heat you reach for fan to help cool you off. As the air is blown across your sweaty body, the air begins to evaporate the sweat and you begin to cool down. The sweat upon your skin attracts the surface heat from your skin as the sweat turns to vapor. This is an example of latent heat.
Another hypothesis, The WISHE Theory (Wind Induced Surface Heat Exchange) suggests that the thunderstorm’s strong winds generated a massive whisking motion on the warm ocean surface, which further enhances the process of evaporation. When water evaporates it absorbs the heat (the energy) from the ocean surface. This water vapor is then thrust upwards to the heart of the hurricane.
When the water vapor eventually condenses, it becomes a water droplet. It is this meteorological mechanism that creates a continuous power source for the hurricane.
The air warmed by this process rises to facilitate a thunderstorm’s growth. The stronger the thunderstorm, the more air is thrust upwards toward the higher levels of the atmosphere. Ultimately, this leads to the air pressure at the surface dropping further. The lower the pressure, the stronger the wind becomes. The stronger winds create more evaporation and so on and so on. The temperature of the ocean water below a hurricane is fundamentally the limit that determines a hurricane’s true only limits a hurricane’s potential.
The Saffir-Simpson Scale
The Saffir-Simpson Hurricane Wind Scale is a codified rating system that evaluates a hurricane’s wind speed against predetermined benchmarks. Major hurricane categories include a Category #3, a Category #4 and a Category #5. These monster storms have significant potential for loss of life and extensive property damage.
The Saffir – Simpson Hurricane Intensity Scale combines the elements of meteorology with those of structural engineering. A hurricane’s sustained wind speeds are the fundamental determinant.
The Formation of a Hurricane is Really a Long Shot
The perfect conditions needed to create a hurricane are a rarity. Logic would then dictate that if a hurricane travels over mountainous land or hits cooler ocean waters, it quickly falls apart. A hurricane fed dry air will weaken and die. Encountering strong winds tears the storm’s center apart. Meteorlogical forces create and destroy hurricanes. It is like a hurricane has a yin and yang energy. Mother nature is always fascinating and worthy of your respect.