Understanding the implications of climate change on naturally occurring phenomena including hurricanes and tornadoes, contrasting and categorizing the two
Written by: Haritha, Akshaya, Kavya
Hurricanes and Tornadoes
Hurricanes and Tornadoes are two of Earth’s naturally occurring disasters which cause immense damage. Even though people have a similar understanding of the two, hurricanes and tornadoes are indeed very different phenomena. Tornadoes are rotating columns of air which extend “from the bottom of a cumuliform cloud, such as a thunderstorm, to the ground,” and “are often visible as a funnel cloud” (1). While tornadoes form on land, hurricanes are storms which come from warm waters, and also have low-pressure centers. Let’s explore their differences and similarities further.
Differences
Hurricanes and Tornadoes differ in more ways than you may be aware of. Although they have their similarities, these two naturally occurring phenomena vary in how they are created, how often they are produced, and certain characteristics that define them. The main difference that we can easily identify is that hurricanes are created in tropical oceans where warm water is present, whereas tornadoes form on land. In order for a column of air to be considered a tornado, the base of the vortex must touch the ground (7). Hurricanes can be fueled through jet streams though, as can tornadoes, which can form in storms which are close to the jet streams (1). Jet streams, which flow between hot and cold air, are narrow bands of strong winds found in the upper atmosphere. Another difference is that hurricanes tend to be much larger and spread out (hundreds of miles) than tornadoes, which range, at most, a ½ mile wide (1). Additionally, the duration of hurricanes can last up to 3 weeks, compared to about an hour for tornadoes. Although hurricanes can last longer, tornadoes can go up to faster speeds, with the most severe ones reaching 300 mph, compared to hurricanes, which are typically less than 180 mph (1). And when we examine the occurrences or rate of tornadoes versus hurricanes, we can see that tornadoes are much more common than hurricanes, which only take place around 10 times in the entire Atlantic Ocean per year, whereas there have been around 800-1000 tornadoes on average per year in the United States alone (1). In terms of preparation and time given before a hurricane or tornado is in a certain area, we are able to have an advance of a few days for hurricanes, but only minutes before a tornado occurs.
What do they have in common?
In terms of the similarities, both hurricanes and tornadoes are made up of strong, rotating winds. Additionally, hurricanes may lead to tornadoes as they “provide all the necessary ingredients to form tornadoes” (2). Hurricanes contain the thunderstorms from which tornadoes can form, with fuel from the warm, moist air they carry. The changes in direction and speed of hurricanes can also lead to their vortices being flipped vertically, causing yet another possibility for the emergence of tornadoes. Generally, both of these natural phenomena have similar structures, with strong, horizontal winds about the center with “strong upward motion dominating the circulation with some downward motion in the center” (4). Another similarity is that the direction of hurricanes’ rotations, and of most tornadoes, are determined by the rotation of the Earth; counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere (4).
Overall, differences, aside, and regardless of similarities between the characterizations of hurricanes and tornadoes, both can cause some serious damage. It is important to learn about these naturally occurring disasters and ensure we are equipped in the case of an emergency, especially as climate change and its effects become more prevalent in our world.
Categorizing tornadoes and hurricanes:
Tornadoes: Tornadoes are categorized based on the “Enhanced Fujita” scale (EF), which measures two components: wind speed and amount of damage caused (7). A EF0 to EF1 category means that it was a weak tornado whereas EF4 and EF5 refer to significantly deadlier tornadoes (7). There are also different types of tornadoes. One of the most powerful tornadoes are called supercells and are formed during long thunderstorms (7). There are also tornadoes that contain multiple vortices, called multiple vortex tornadoes.
Hurricanes: Hurricanes are categorized by the speed of their winds. There are five categories of hurricanes ranging from 74 mph in category 1 to higher than 160 mph winds in category 5. As mentioned previously, the hurricanes in the northern hemispheres rotate counterclockwise and clockwise in the southern hemisphere (8). This rotatory difference is due to the Coriolis effect (8). Hurricanes are named alphabetically starting from A each year and alternate between boy and girl names.
How is climate change affecting their patterns?
Although there is little evidence that the frequency of tornadoes has been increasing in the present, there is evidence that the ‘power’ of tornadoes has been increasing (3). However, there has been an inconsistency in the rating of tornadoes, especially until the 1990s, when the number of tornadoes were based on someone spotting a tornado and reporting it to the National Weather Service (3). Multiple tornadoes do seem to be an increasing phenomenon (3). Similarly, in the future, although the frequency of hurricanes may not increase, the intensity of hurricanes is expected to increase with higher wind speeds, and greater amounts of precipitation (5). One of the major factors that could play a role in increased hurricanes, especially in the North Atlantic, are rising ocean temperatures. When surface waters rise above 26 oC, warm, moist air rises and fuels the storm, as warm air holds more moisture than cold air (5). Increased moisture leads to more cloud formation and greater amounts of precipitation, thereby intensifying hurricanes.
Most recent hurricanes and tornadoes
Hurricane Katrina was one of the financially devastating hurricanes to hit landfall in the United States in modern day America (6). It caused storms on the Mississippi coast in 2005, with damage extending several miles inland (6). Although this was a category 3 hurricane, it cost property damages of around 125 billion USD (6). Hurricane Harvey in 2017, which was a category 4 hurricane, hit landfall in San Jose, Texas (6). The damage cost approximately 125 billion USD due to excessive flooding and the destruction of half a million vehicles and three hundred thousand buildings (6).
What is the future going to be like?
Hurricanes: Although the frequency of tropical storms are predicted to decrease or remain unchanged, climate change will increase the intensity of the storms. There will be more rainfall with hurricanes as the temperature of the planet increases (9). With more moisture in the air, rainfall will be heavier and will result in floods. Additionally, hurricanes of category 4 and 5 are predicted to increase (9). This will result in a great amount of infrastructure damage.
Tornadoes: There are still ongoing investigations to see how exactly climate change will affect tornadoes. It is predicted that as a result of increase in warm air and moisture, there might be an increase in frequency of tornadoes (10). Research on tornadoes is limited around the world as it is a phenomenon that mainly occurs in the United States. In recent years, the pattern of tornadoes seem to be shifting to areas of high population density, potentially resulting in great damage (10).
Closure:
Although research is vital in understanding the severity of these natural disasters, there is not a fool-proof method to predict the severity of these storms in the near-future. Therefore, it is important to understand the patterns that are being observed and take action accordingly. As we have seen, climate change influences almost every aspect of global weather, if not all. It is our responsibility to partake in mitigating the potentially catastrophic events that not only threaten our existence, but the future of life on this planet.
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