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What Can Make a Hurricane Lose its Power

What Can Make a Hurricane Lose its Power

Lot has been said and written about the origin and causes of hurricanes. But the factors that control the intensity of hurricanes are still lying in poor light. Wind shear and dry air are believed to make a hurricane lose its power, thus dissipating it.
Ashwini Kulkarni Sule
Hurricanes are one of the strongest and devastating natural disasters. They are strong, powerful winds that claim the lives of millions of people all over the world and cause infinite damage to property. They originate in the ocean as a result of tropical disturbance and pass through two initial stages, namely tropical depression and tropical storm, before becoming lethal weapons of mass destruction. Hurricanes last for a week or so before dying down on their own. However there are certain factors which control the intensity of hurricanes.

Factors Responsible for Dissipating Hurricanes

There are several tropical factors responsible for the formation of hurricane. Hurricane gains its energy from warm, moist air. In the absence of these factors, chances are that it will soon subside. The natural factors responsible for dissipating hurricanes are:

Landfall
Most hurricanes lose their power very rapidly after making a landfall. They become more and more disorganized in the areas of low pressure or sometimes may evolve into extratropical cyclones. If the tropical cyclone manages to come across open, warm water, there are chances of regeneration. If it remains over mountain terrains even for a short time, it will rapidly start losing whatever energy is left in it. This could prove fatal as the dying storm often unleashes torrential rainfall, leading to deadly floods and mudslides.

Staying in Ocean for Long
Dissipation may occur if a storm stays in the same area of ocean for too long. Due to this, sea surface temperature may drop by more than 5°C (9 °F). And as the storm cannot survive without warm surface water, it eventually subsides.

Vertical Wind Shear
Weakening or dissipation can occur if a hurricane experiences a vertical wind shear. The effect of convection causes the heat engine to drift away from the center. This helps to cease the advancement of a tropical cyclone.

Artificial Dissipation
Several attempts have been made to artificially dissipate the hurricanes. In the 1960s and 1970s, the United States government initiated a 'Project Stormfury' which aimed at weakening the hurricanes by seeding selected storms with silver iodide. The basic idea was that the seeding would cause supercooled water in the outer rainbands to freeze, breaking the inner eyewall and eventually reduce the winds. The result was such that the count of winds of 'Hurricane Debbie' - a hurricane seeded in Project Stormfury, fell to 31%. But Debbie regained its strength after two attempts of seeding were made.

Earlier, disaster had taken place in 1947, when a hurricane in the east of Jacksonville, Florida promptly changed its course and smashed into Savannah, Georgia, immediately after it was seeded. Since there was a lot of uncertainty involved about the behavior of these storms, the federal government stopped approving seeding operations unless the hurricane had less than 10% chance of making a landfall within 48 hours. This substantially reduced the number of possible test storms. The project was finally dropped when it was discovered that eyewall replacement cycles occur naturally in strong hurricanes. This brought the results of earlier attempts under suspicion. Now it is a known fact that since the amount of supercooled water in the rainbands of a tropical cyclone is very low, there is nothing a silver iodide seeding can do.

As evident from above, the hurricanes arise and subside in a natural way. Human intervention does little to stop the brutal forces of nature. Hence it is our responsibility to take all safety measures and protect our homes and family when a hurricane strikes.
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