A tornado is a low pressure system that is spinning at a very fast speed. Tornadoes are formed in three steps, first a rotating body of air forms on the ground because of wind sheer, second horizontal rotating air is lifted off the ground by the updraft of a thunderstorm. When the horizontally rotating air mass is lifted vertically it is considered a mesocyclone. And finally, this mesocyclone is fully developed in the updraft of a thunderstorm meaning the tornado will come from the slowly rotating “wall cloud” in the lower part of the cloud.
In the US tornadoes usually travel Northeast but this si not true for the entire world. Tornadoes do not travel in the same direction
in different regions of the world because of the different conditions and air
that changes with location. So the winds
and conditions that occur in the US will not be the same in South Africa.
The average number of Hurricanes that occur in the US is about 1,253 on the other hand South Africa does not experience hurricanes every year and they occur only once in a while about 0.4 times per year.
Hurricanes:
Hurricanes are also very low pressure systems and are considered the "greatest" storms on earth. The three main requirements for hurricane
formation are 1. Warm ocean temperatures
over 80 degrees F because lots of evaporation is needed. This is why hurricanes are created equator-ward
20 degrees north and south. The second
thing that is needed is a deep warm ocean layer about 200 meters in depth. This is so that when being mixed, the water
will still be warm. The final
requirement is Coriolis as it is needed to initiate the spinning of the hurricane,
this is why hurricanes start between 5 degrees north and south.
In different regions hurricanes have different names, in the Atlantic and East pacific they are
called Hurricanes, in the Indian Ocean near Australia, they are called Cyclones
and off the coast of China and Indonesia, they are called Typhoons.
As seen in the picture above, hurricanes around the US usually travel in a "c" shape and this is because of the winds. The
westerlies push the hurricane out and they dissipate when the reach colder
waters.
Hurricanes have hit South Africa before but it is not a frequent occurrence because it is a little far from the equator and does not have the perfect conditions but when they do happen, they do not go in the same direction
because South Africa is located in the southern hemisphere so the winds like
the westerlies go in the opposite direction curving the general path of
hurricanes downward. When comparing the average of 4 hurricanes that his the US every year, hurricanes only hit South Africa once in a great while.
Geographic Location and Comparison to US:
South Africa is located at 29 degrees south latitude and 24 degrees East longitude. It is also surrounded by two oceans the Indian Ocean, and the South Atlantic ocean. In South Africa tornadoes can occur, but definitely not
as often as the occurrences in the US. Also,
since South Africa is located in the Southern Hemisphere so hurricane season is
opposite. Hurricanes on the other hand
do no affect South Africa very often as they are only affected once in a very great
while. This could be because waters near
South Africa are too far from the equator and therefore too cold.
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