It was supposed to have pounded the coast of Florida and even delayed Republican Presidential candidate Mitt Romney's nomination by a few days. But hurricane Isaac changed course midway. After barely grazing the Florida Keys, it bypassed the rest of the Sunshine State and instead, unleashed its fury on the three Gulf states of Louisiana, Mississippi, and Alabama.
The hurricane's timing was particularly eerie for the residents of New Orleans given that it landed on Tuesday, August 28th - Seven years to the day after hurricane Katrina almost erased the city off the world map. What was even scarier was that just like Katrina, Isaac began as vast storm leading experts to wonder if it would develop into a similar kind of monster hurricane as it blew across the warm Gulf waters. Thankfully, that did not happen.
But Isaac still ended up a very powerful category 1 hurricane that tested the coastal city's 130-mile, 14.6 billion new levee system, and floodgates to the fullest. The storm that has resulted in six deaths has caused widespread flooding, leaving thousands homeless and almost a million residents of the Southern States without power. One of the hardest hit is the Plaguermines Parish that lies fifty miles southeast of New Orleans. The area that comprises of fishing towns, marinas and marshland is exceptionally vulnerable to flooding because portions of it lie outside the levee protection system.
Now downgraded to a storm, Isaac is currently making its way through Missouri where it is expected to dump its remaining moisture - between 3-5 inches this weekend, before petering out. The rain will definitely be welcomed in this drought-stricken area that has not received much precipitation this year.
So what causes these unstoppable acts of nature? In this article, we go behind the scenes to examine how and why hurricanes happen and if there is anything we can do to stop them.
Though scientists have been studying hurricanes for only the last one hundred years, there is evidence that these powerful storms have been going on for much longer. In fact, the name hurricane is thought to have evolved from the word 'Hurakan' - One of the gods of the ancient Mayan civilization that inhabited Mexico around 900 AD. The Mayans believed that Hurakan caused these storms by blowing his breath across the water. In 1400 AD the Carib Indians, who lived in the West Indies Islands re-named the storms 'Hurican', or god of evil.
What Are Hurricanes?
Hurricanes also known as cyclones in some parts of the world, are super powerful storms, which gain momentum from winds that help them blow in at speeds ranging from 75 to 225mph, resulting in massive destruction when they hit land.
How Do They Occur?
For hurricanes to occur, the ocean temperatures must be at least 80°Fahrenheit and the atmosphere around it, saturated with moisture. Also, the winds must be blowing in the same direction and the same speed to force the air upward from the surface of the ocean.
What Happens Then?
The warm water creates low-pressure air, causing it to rise. As the air rises, it collects moisture-forming thunderclouds. Meanwhile, cool air displaces the space created by the warm air that has risen. As the warm air condenses, it produces even more heat and rises even faster, causing more cold air to rush in. This increases the intensity of the storm. As the hurricane winds rotate, they accumulate water in the center of the storm. This water, called the storm surge, is the most deadly part of the hurricane, because it dumps into any landmass it hits, causing floods and devastation. The bigger the storm surge, the more powerful the hurricane.
The Coriolis Effect
When a hurricane first begins, the rising winds blow in towards the center of the storm. However, as it grows, it gets impacted by what is known as the 'Coriolis Effect.' This is when a force, in this case, the Earth's rotation around its own axis, deflects objects on one side. So, while the hurricane is attempting to go straight, the Earth's movement causes it to deflect to the right, forcing it to go counter-clockwise, in the Northern Hemisphere and clockwise in the Southern Hemisphere.
Why does each hurricane have a name?
Hurricanes are given names so that scientists can track the storms from start to finish. In the fifties, hurricanes were named after the phonic alphabet, like Able, Baker, etc. From 1953-1979, the US Weather Bureau decided to shift to only women's names. Since then, they have alternated between male and female names and now have six different name lists that they alternate each year. If a hurricane causes real major devastation like Katrina did to New Orleans in 2005. The name is replaced with another name and never used again.
What can we do to stop them?
Unfortunately, not much. In the past, scientists have tried various inventions to weaken these storms. But they gave up in the 1960s after realizing that the weather patterns were too large to affect. Instead, they changed their focus to understanding how hurricanes form and move so that they could predict their timing and intensity with greater accuracy. But like other acts of nature, this too remains an inexact science - One that is neither completely predictable nor, controllable.
What do the hurricane categories mean?
The hurricane categories, which range from 1-5, are simply a way to gauge their intensity, with 5 being the worst.
Given that a typical season sees about six hurricanes and the fact that the peak of the season is not until the end of September, there will probably be a few more big storms before it's all over. The good news is that Isaac is the fourth hurricane of the 2012 Atlantic season - The first three did not land on US soil. So maybe we will escape the rest too, which would make this the best hurricane season we have had in many years.
Resources: usatoday.com, chicagotribune.com,huffingtonpost.com,abcnews.go.com