Hurricane: The Storm with the Winds of Fury

The name Hurricane is derived from the Carib Indian's name Hurican, which translates to the god of evil. You may agree with the aptness of the name if you've witnessed one in action. The Caribs are the dominant tribe of people living in Central America part of Dominica, of which the Carribean owes its name to this tribe.

Imagine a wind and storm so powerful that the spinning wind exceeds a speed of 185 miles per hour ( 297 kilometres per hour). At that ferocious speed, houses and things that lies on their paths are set up for total obliteration. If you could imagine such a scenario happening in real life, you have just imagined a hurricane.

^{Photo by NASA on Unsplash: A Hurricane}


A hurricane is a special type of tropical storm that swirls with accompanying wind speeds of 74mph (119kmh) or more.

There are similarities between a hurricane, a cyclone or a typhoon. A tropical cyclone has the same property of a hurricane; it comes with a swirling or rotating wind property. The only difference is its speed is less than 74 miles per hour. If a tropical cyclone hits a wind speed of up to 34mph, it is now a tropical storm.

The typhoon is just the same as a hurricane but occurs over the Northwest Pacific Ocean. Whereas, the hurricanes are formed over the Northeast Pacific and North Atlantic Ocean.

Apart from the speed, cyclones also occur over the Southern Pacific Ocean and the Indian Ocean.

The making of a hurricane

We all know how large and devastating a hurricane could be. A hurricane at its peak can cover up to 100 miles (160km). The inside of the hurricane, which constitutes of "walls" of ice and clouds, extends upwards to about 10 miles (16 km).



^{[Wikipedia]Source}


To have these dynamics at play which results in a hurricane two physical phenomena work together to achieve that. They are the heat and wind.

The heat effect

The winds flow towards the centre or eye of the hurricane. Under normal circumstances, due to the low pressure of the area, the breeze will cool that part. But due to the ongoing massive evaporation, each gallon that evaporates has the thermal energy property of one cup of petrol. Remember evaporation causes cooling as it takes heat away. The evaporated water condenses in the atmosphere.

The evaporation continues with the upward movement of moist air. This updraft creates a low-pressure point. Wind from the high-pressure part of the atmosphere gets sucked into this low-pressure section.

The rising moist air condenses and feeds more energy to the air creating more clouds and rains.

The spinning effect of wind due to Coriolis Effect sets in along the line. Coriolis Effect is the spinning effect of the earth on wind direction.

At about 40,000 feet, cold, dry air forced from the storm's peak sinks downwards in the storm following the eye of the storm. This creates an area that is devoid of rain.

The Power Monster

A well-formed hurricane has the capability of producing 1.5cm/day rain through a 665km radius. The thermal energy equivalent (energy expended during evaporation of water) is a massive 6.0 x 10¹⁴ Watts or 5.2 x 10¹⁹ Joules per day.

This thermal energy generated is equivalent energy that is 200 times the required world's energy according to the National Oceanic and Atmospheric Administration website on hurricane matters here.

Or according to NASA.

during its life cycle a hurricane can expend as much energy as 10,000 nuclear bombs!^NASA

The destruction of lives and properties due to sea surges and flooding makes hurricanes a dreaded natural disaster. For instance in 1998, Hurricane Mitch left about 18,000 dead in 1998 in Central America.

Weather 101

The pressure of the atmosphere plays an essential part in the weather of the day. Listening to the weather forecast you may hear the weatherman make mention of a particular area as low-pressure point and thus to expect rain or a high-pressure point to have beautiful weather.

This forecast is based on how pressure (high or low) affects air.

Air flows from the region of high pressure to the area of low pressure. The wind blows in the direction of the low pressure, and air that rises makes the moist water to form condensation creating precipitation. These low-pressure points are marked with a red "L" on a weather map.

Due to earth's rotation and Coriolis Effect, the low-pressure winds deflect and swirls anti-clockwise for winds in the North of the Equator and clockwise direction to the South of the equator. This phenomenon is known as the cyclonic flow.

If it is a high-pressure system, wind behaves the opposite and blows away from the high-pressure area. The direction of flow also reverses: anticlockwise for the South of the equator and clockwise for the North of the equator. This high-pressure point is usually depicted by a blue "H" in the weather map.

^{[Wikipedia]Source: The weather formation}

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The wind migration from the area of low pressure to an area of high pressure results in the massive winds that are the hallmarks of every hurricane.

The swirling hurricane's wind follows the Coriolis Effect of produced by the Earth's spin. If the earth were to be stationary, the wind of the hurricane would move in a straight line.

The 74-mile+ speed wind blowing along the North of the equator also has some elements of it blowing Eastward (the Earth's rotation path), so it apparently gets deflected to the right or the east.

The opposite is what happens when the air moves towards the South of the equator and encounters a faster surface speed. It deflects westward or to the left.

This wind's defection according to the earth's rotation is how the Coriolis effects give the storm its swirling effect. That also explains the difference in direction. The cyclones spin at the anticlockwise direction in the Northern hemisphere and rotate clockwise in the Southern hemisphere.

Hurricanes hardly form at the equator because of this too. This lack of hurricane formation is due to the insufficient difference in the rotation that is apparent at those low latitudes of the equator.

For more pictorial representation of this explanation check this picture here.

^{Image Reference
Image 1: Coriolos Effect
Image 2: Coriolis Effect Showing Clockwise and Anticlockwise effects}

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^{References
A Brief History of Hurricane's Name
Hurricane, Cyclone and Typhoon
Energy of a Hurricane
Anatomy of a Hurricane}

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