Take a close look at these photos of hurricanes and cyclones—do you see the similarities,
or rather, do you see any differences?
To an untrained eye, all these images may look nearly identical, but if you look closely,
you’ll notice that some of these have the hurricane spinning in the clockwise direction,
while others show the storm spinning counter-clockwise.
So… what’s that all about?
Why do some hurricanes spin in one direction while others spin the opposite way?
You may already know that hurricanes, cyclones and typhoons are different names for the same
natural phenomenon—a tropical cyclone.
In essence, they’re all very violent storms that originate over oceans and seas and move
towards land, potentially causing extensive damage to both life and property.
They are caused by pre-existing weather disturbances, moist and warm air, warm tropical oceans and
relatively light winds.
Despite essentially being the same natural phenomenon, these storms are given different
names based on the geographical region where they originate.
According to the National Oceanic and Atmospheric Administration (NOAA), hurricanes occur in
the North Atlantic Ocean, the Northeast Pacific Ocean, or the South Pacific Ocean.
That’s why in the US, you will mostly hear the term ‘hurricane’ in reference to these
storms.
Typhoons, on the other hand, occur in the Northwest Pacific Ocean, while cyclones occur
in the Southwest Pacific Ocean and most parts of the Indian Ocean.
A cyclone originates over warm ocean waters in the equatorial region of the Earth.
The warm, humid air above the water surface rises up, creating a low air pressure zone
in its wake.
Cold air rushes in to fill this void and then gets heated up, at which point it rises up
to form clouds.
As this cycle continues over the oceanic water surface, the clouds grow bigger and bigger,
wind speeds increase and the tropical storm takes the form of a cyclone.
Interestingly, cyclones in the northern hemisphere of our planet spin in the counterclockwise
direction, while those that occur in the southern hemisphere spin clockwise.
In fact, this is true for all storms.
This happens due to the Coriolis Effect—a physical phenomenon named after the French
mathematician Gaspard-Gustave de Coriolis.
Put simply, the Coriolis Effect works in a way that it makes things travelling long distances
around the Earth appear to move in a curve, rather than a straight line.
It is a very powerful force that affects weather patterns, ocean currents and even airplanes.
The Coriolis Effect comes into play because different parts of the Earth rotate at different
speeds.
Our planet rotates faster at the Equator than it does at the poles.
It’s wider, or more technically, has a greater circumference at the Equator.
Therefore, in order to complete one rotation in 24 hours, the equatorial regions experience
a much higher rotational velocity than other parts of the planet.
Standing at Earth’s north pole, if you were to shoot an arrow at a target in the southern
direction, towards the equator, the arrow would land west of the target, as the Earth
rotates from west to east.
But if you shoot an arrow from the equator at a target towards the north pole, then the
arrow would land east of the target.
Similarly, in the southern hemisphere, the arrow shot from the south pole towards the
equator would land west of the target, whereas the arrow shot towards the south pole would
land east of the target
The same thing happens when winds, storms and cyclones in the northern and southern
hemisphere travel from and towards the equator.
In both hemispheres, winds traveling towards the equator are diverted towards the west,
while winds traveling towards the poles will curve eastwards.
But due to the presence of low pressure zones, these winds follow a circular path.
This is why cyclones and hurricanes in the northern hemisphere spin counterclockwise,
whereas those in the southern hemisphere spin clockwise.