Causes and Effects of Hurricanes

Hurricanes are the most destructive natural disaster; they are very powerful and violent storms, often associated with strong winds and heavy rains. A storm is classified as a hurricane when the speed of wind reaches 74 miles (119 kilometers) per hour. Hurricane storms usually start over warm sea (near the equator) and are accompanied by fierce winds, flash floods, mudslides and huge waves.

Hurricanes are assigned with different names, depending upon the area where they have occurred. For example: hurricane storms are called hurricanes, if they start over the Caribbean Sea, the Northeast Pacific Ocean and the North Atlantic Ocean; whereas, storms are called tropical cyclones, if they occur in the Indian Ocean or near Australia. Let's take a look at the causes and effects of hurricanes.

Causes of Hurricanes

There are two main factors that are responsible for causing hurricane storms, viz. warm water and moist, warm air. Hurricanes occur when the moist, warm air from the surface of the ocean rises and meets the cooler air. In such a situation, the moist, warm air condenses and forms storm clouds and raindrops. There is also release of latent heat due to condensation process, which increases the temperature of the cooler air above. In the cycle, more warm, humid air from the ocean surface rises and joins the developing storm. Hence, there is a transfer of heat from the surface of the ocean to the atmosphere above.

As the cycle of exchanging heat continues, a wind pattern is created that moves in a spiral fashion around a calm center, which is referred to as the hurricane eye. Converging winds near the ocean surface collide with the developing storm, resulting in an increased circulation of warm, humid air and also enhancing the speed of wind. Presence of strong winds at high altitude pull the rising warm air away from the center, causing the storm to swirl in the typical cyclone pattern.

Another factor that increases the speed of wind is high-pressure air at high altitude. This high-pressure air draws the heat away from the center of the storm. As this high-pressure air moves to the center and meets the low-pressure air, the wind speed again increases.

Effects of Hurricanes

When a powerful hurricane hits land, it can cause more damage to life and property than any other natural disaster. The effects of hurricanes include storm surge, strong wind, inland flooding and tornadoes.

• Storm surge is the most devastating effect that accounts for 90 percent of the hurricane deaths. It refers to the rapid rise in the level of water that comes ashore, as the hurricane hits land.
• The overall effect of a hurricane depends on speed of the wind. It helps to determine the force of the hurricane storm, the storm surge and the damage that the storm can cause.
• It is a fact that inland flooding causes more deaths than the actual hurricane storms. On an average, 5-10 inch rainfall is common. However, rainfall may increase depending upon the storm.
• Hurricane storms may also result in tornadoes. However, the frequency and occurrence vary from one hurricane storm to another. Very often, such tornadoes are of minimal strength.

An example of powerful storms is the Hurricane Katrina on August 29, 2005, which struck the United States, causing death of more than 1,800 people and property damage worth $81billion. It was the costliest hurricane in the history of US. Though, heavy rainfall may prove to be beneficial at times of drought, the overall effects of hurricanes are more devastating. Some researchers are of the opinion that hurricanes are caused due to climate change and/or global warming. However, studies are ongoing to study the relation between climate change and hurricanes.