Tropical cyclones are the most destructive and violent type of storms. Fortunately, their fury and destructive effects are limited to islands and coastal settlements. The damages to life and property caused by them fall into three categories: (a) damages caused by high velocity winds, (b) damages caused by flooding, and (c) damages caused by a storm surge.
A great deal of destruction to man-made structures and vegetation is done by strong winds in a hurricane. Trees are uprooted and broken, and the loose objects swept away. The worst affected areas are invariably those near the coastlines.
As the storm moves over land, there is a rapid decrease in the wind speed. On several occasions, coastal cities and their inhabitants have suffered tremendous losses of life and property. When a terrible tropical cyclone strikes a human habitation, the buildings are destroyed and thousands of persons are killed.
Torrential rains that occur in a hurricane from its towering cumulonimbus clouds inundate the low-lying areas, cause floods and landslides resulting in a great loss of life and property damage.
Besides, storm waves of great heights, sometimes about 5 meters, are a great hazard to shipping. When these high sea-waves break on the coastal land, they do great damage.
According to many weather scientists, by far the greatest damage and loss of life and property from intense tropical cyclones are due to storm surge. The rise in sea level because of the passage of a hurricane is called the storm surge.
Under certain conditions waves generated in different segments of the storm cross each other and attain abnormal heights ranging from 15 to 20 meters. Such waves are reported from the Atlantic and the Pacific Oceans.
Sometimes a ship entering the eye of a cyclone may experience calm or light and variable winds, but the sea, on the contrary, will be very rough because of the waves coming in from various sides.
The most violent storm of Pakistan in 1970 offers a typical example of a storm surge. Similarly, Camile hurricane of the Gulf of Mexico in 1969 has gained notoriety for the havoc played by the storm surge produced by this fierce storm.
At times, a hurricane wave caused by the damming effect of the wind on the forward side of the central region is superimposed on the tidal wave. If the hurricane wave combines with the spring tide, the result is disastrous.