Low-pressure areas may hover over the earth’s warm oceans during the summer and fall, sometimes with catastrophic results. Hurricanes may wash away homes or kill thousands of people. The strongest hurricanes, Category 5, can reach wind speeds of more than 155 miles per hour. Restoration efforts in the wake of a hurricane may take years. Several factors play into the destructive abilities of hurricanes.
The Effects of the Sun
The sun sets hurricane activity into motion when it heats water. This warm water provides an essential fuel source for hurricane development. Warm air rises into the atmosphere while cool air falls into a low-pressure area. These low-pressure areas result in water evaporation, which develops humidity in the air. As more warm air rises, more cool air replaces it, leading to increasingly strong winds. The disturbance officially reaches hurricane status when its wind speeds reach 74 miles per hour.
The Contribution of Easterly Waves
As heat moves from the sea into the sky and cool air moves from the sky into the sea, other contributing factors can cause the disturbance to transform into a hurricane. In the Atlantic Ocean, one of the contributing culprits is the African easterly wave, a tropical wind. It can play a role in rain showers and thunderstorms, but also contributes to more than eight out of 10 major hurricanes in the Atlantic Ocean. The African easterly wave passes through the intense heat of the Saharan Desert and the comparatively cooler regions of the Gulf of Guinea before it moves into a low-pressure area.
Earth is home to seven ocean basins scattered about the globe, with each of the basins housing the warm water that hurricanes feed upon. In addition to the temperature, the water’s depth and wind currents also contribute to the development of hurricanes. These factors can help determine the severity of a tropical storm or hurricane. One of the deadly contributors to the power of 2005’s Hurricane Katrina’s storm surge was the presence of shallow, offshore water for fuel.
Scientists predict that global warning may not only mean the death of the polar ice caps, but also could lead to more cataclysmic natural disasters, such as an increase in hurricanes. The global warming theory maintains that greenhouse gases will contribute to the warmth of the world’s oceans. As oceans warm up, they provide the catalyst for hurricanes to develop. Scientists predict that while global warming may increase the severity of hurricanes, it also may decrease the number of hurricanes that occur.
Wind shear plays an important part in the development, death and even the intensification of hurricanes. Wind shear refers to differences in the direction or speed of wind as it travels a straight line. Wind shear can remove the heat and moisture from a tropical storm or hurricane, reducing its power or destroying the storm altogether. On average, as wind shear increases to more than 20 knots, hurricanes may diminish or disappear. As wind shear falls below 20 knots, hurricanes can intensify.