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Storm surge
The most destructive part of a cyclone, and the one in which people usually lose their
lives, is a storm surge. This is a sudden high wall of water that is pushed on to the
land from the sea by the strong winds that blow around a storm. It is caused by a
combination of low pressure, very high winds, and high waves.
Surging with the tide …
Storm surges are more destructive when they occur during high tides. Tides are the daily
rising and falling of the water in seas and oceans due to the movement of the earth, sun,
and moon. During high tide, the water rises higher than its normal level. If there is a
cyclone at such a time, the water that is pushed by the wind rides on top of the high tide.
This creates storm surges that can be over five metres high. Hurricane Katrina, which hit
the US in 2005, generated a storm surge that was 7.5 metres high.
Faster, stronger, higher …
The height of a storm surge depends on the wind speed. The higher the speed, the more
will be its pushing power. The speed at which a cyclone moves forward also contributes to
the height of a storm surge. The faster it hits the land, the higher will be the piling up
of water.
A coast that leads down to a sloping sea floor has greater storm surges, while a coast with
high cliffs is not in much danger, as the waves break against it.
A Category 2 A Category 3
hurricane can hurricane can
create storm create storm
A Category 1 surges that are surges that
hurricane can more than two are almost 3.5
create storm metres high. metres high.
surges that
are more than
one metre
high.
A Category 5
A Category 4 hurricane can
hurricane can create storm
create storm surges that
surges that are more than
are almost five 5.5 metres
metres high. high.
TICKER Heavy rainfall dumped by cyclones, combined with storm surges, increases the level of water
The most destructive part of a cyclone, and the one in which people usually lose their
lives, is a storm surge. This is a sudden high wall of water that is pushed on to the
land from the sea by the strong winds that blow around a storm. It is caused by a
combination of low pressure, very high winds, and high waves.
Surging with the tide …
Storm surges are more destructive when they occur during high tides. Tides are the daily
rising and falling of the water in seas and oceans due to the movement of the earth, sun,
and moon. During high tide, the water rises higher than its normal level. If there is a
cyclone at such a time, the water that is pushed by the wind rides on top of the high tide.
This creates storm surges that can be over five metres high. Hurricane Katrina, which hit
the US in 2005, generated a storm surge that was 7.5 metres high.
Faster, stronger, higher …
The height of a storm surge depends on the wind speed. The higher the speed, the more
will be its pushing power. The speed at which a cyclone moves forward also contributes to
the height of a storm surge. The faster it hits the land, the higher will be the piling up
of water.
A coast that leads down to a sloping sea floor has greater storm surges, while a coast with
high cliffs is not in much danger, as the waves break against it.
A Category 2 A Category 3
hurricane can hurricane can
create storm create storm
A Category 1 surges that are surges that
hurricane can more than two are almost 3.5
create storm metres high. metres high.
surges that
are more than
one metre
high.
A Category 5
A Category 4 hurricane can
hurricane can create storm
create storm surges that
surges that are more than
are almost five 5.5 metres
metres high. high.
TICKER Heavy rainfall dumped by cyclones, combined with storm surges, increases the level of water
