Tropical storms are the heat engines of the nature. They take up a near circular shape with empty space in the centre called the eye. It is nothing but the low pressure area around which the most intense thunder storms revolve. If the storm is strong, a clear eye occurs and when it is power goes down, the eye is filled by clouds. Tropical storms depend on ocean heat content, moisture in the atmosphere. That is why most tropical storms form in sea and once on land it keeps weakening. Its track depends on pressure difference, moisture content. It leaves behind a cool stretch of sea surface where another tropical storm usually does not form in the same season.
In Atlantic Ocean the storms take up the name as hurricanes. In sub Saharan desert small low pressure areas are created which once in Atlantic hot water, creates a lot thunder storms. These thunder storm systems gets well organized to form tropical cyclone and take up the route towards US, Bahamas, West Indies, Canada, Cuba and Mexico.
In Indian Ocean before or after monsoon season easterly waves create a low pressure area in lower Bay of Bengal or Arabian Sea. These lows then organize it self to form Cyclones and lashed towards sea cost of India, Bangladesh, sea cost of Oman and Pakistan. As these areas are densely populated, the causality is too much high due to the cyclones. [Remarkably the Bhola cyclone and 1991 Bangladesh cyclone].
In Pacific Ocean these tropical storms take the name as typhoons. Typhoon Tip is still the largest tropical cyclone formed in any basin compared to size. They too form from the easterly waves and slam in Filipino areas, mainland china, Taiwan, Japan and Hong Kong and South East Asian countries.
Two tropical storms when near to each other revolve around each other. The bigger one ultimately engulfs the smaller one. This cannibalism in tropical storms is called Fuiwhara effect.[mostly in west pacific typhoons]
Now-a-days, due to global warming outside eye wall, condition becomes favorable for creation of another eye wall. To surround the eye the battle of eye walls begin. [just like in hurricane Katrina, hurricane Ike].This battle of eye walls provides data about the strength of the tropical storm.[defines explosive intensification]
While this kind of fight ensures two eye walls come into the picture or the ringed eye wall. The ringed eye wall system do not last for longer period and the ring gets destroyed and single eye is again created. [Mostly in west pacific typhoons]
Wind shear always plays a vital role in storm intensification. More is the wind shear [ie vertical wind shear] less is the storm ferocity. In all cases when wind shear is less powerful storms take shape.
When tropical storms hit land, they bring lot sea water, which in turn inundate the coast line. This flood of sea water by tropical storms is called as storm surge. Most casualties take place due to storm surges, rather than the storm itself.
Tropical storms intensity and wind speed is calculated by a scale called as Saffir Simpson scale. Here storms are categories of tropical depression, tropical storm, category -1 hurricane, category-2 hurricae, category-3 hurricane, category-4 hurricane, category -5 hurricanes. Out of which cat-4 and -5 storms are most intense and violent, but less power storms are also powerful to cause havoc, if they pass on heavily populated areas.
So we need to keep a watch what is happening in the sea and predict these storms well in advance to protect the shore line folks.