Introduction
Hurricanes are some of the most intense forces of nature, capable of generating wind speeds of over 150 miles per hour and causing great amounts of destruction. In 2005, Hurricane Katrina caused levees to break in New Orleans, which resulted in city flooding and hundreds of lost lives. In 1992, Hurricane Andrew swept across southern Florida and demolished entire neighborhoods. Thousands were left homeless. Seeing the impact of such mega-storms, I decided to map out hurricane proneness across the United States in order to identify the areas of highest hurricane risk. Those areas which typically endure hurricanes more than others should be examined with a discerning eye to ensure that evacuation procedures are reliable, adequate supplies will be available, and so on. These maps can be useful in deciding where to move. Moving into an area of higher hurricane risk means buying window shutters and having them be readily accessible. One afternoon in Fall, residents may be asked to board up their homes and evacuate, possibly to never see them again.
Methods
I made maps showing the hurricane-proneness of states and counties. First I made the map to see what the most hurricane-prone states were, and those were the states I chose to analyze hurricane threat on at the county level. I found a shapefile of all previous Atlantic hurricanes from 1851 to 2008. This shapefile was comprised of many individual line segments however, as opposed to pre-assembled full linear courses of the hurricanes. This caused me to do a lot of different types of selections and categorizations to be able to show the hurricane paths based on their category ranking on the Saffir-Simpson Hurricane Scale. This scale goes from 1 to 5, and is used to categorize hurricanes based on their wind speed. Category 1 hurricanes have wind speeds between 74 and 95 mph, while category 5 hurricanes have winds of over 156 mph. Categorizing the storms by this scale was tedious because each small line segment had its own wind speed value of the storm at that particular point along its path. For instance, a category 5 hurricane will have category 1 and category 2 line segment attributes. I found that the most efficient way to accomplish my task was to group together the storms by their identification numbers to ensure they would be displayed as a whole. I plotted every Atlantic hurricane that occurred from 1988 to 2008- twenty years worth- in order to be able to get an idea of where the most common places for hurricanes to strike are over time. In order for a state or county to be considered to have had a direct impact by a hurricane, the hurricane must have either intersected, or have come within 29 miles of the specific polygon. Twenty-nine miles is the average radius of maximum wind, which is located around the eye wall of a hurricane. Although damage can definitely occur, and people hundreds of miles away from the eye of the hurricane can feel and observe its effects, this analysis focuses on those generally impacted the greatest, the places within the radius of maximum wind. I calculated the total number of hurricanes that intersected or came within 29 miles of states over the twenty years. After I got my values per state, I divided the number by 20 in order to provide the average number of hurricanes a place has per year. Most states have a decimal below one, but the two highest, North Carolina and Florida, have averages of 1.3 and 1.0 hurricanes respectively per season. These are the two states I analyzed county hurricane proneness for. County analysis was similar to state analysis, as I would click each county one by one to select it, and perform a select by location based off of it to see how many hurricanes have at one point moved through that spot.
Results
As I mentioned, North Carolina and Florida had the greatest amount of hurricanes come within 29 miles of them as opposed to any other states from the years of 1988 to 2008. All of the states bordering the Atlantic Ocean or the Gulf of Mexico showed hurricane activity. Most of the western states show none. There are generally higher concentrations of more hurricane-frequent states in the south as opposed to the north, which is correlated to a hurricane’s need for warm waters to perpetuate it. Mapping the counties of North Carolina and Florida made me very clear on the effect proximity to the Ocean has of hurricane frequency. North Carolina looks as though it is divided in half by the symbolic colors representing frequency of hurricanes. The western, inland portion of the state has very little hurricane activity compared to that of the coastal region. The average number of hurricanes a western North Carolina county experienced during the twenty years was about two or three, and near the coastal region that number is more along the range of nine or ten. It’s also interesting to look at the types of storms that affected different regions and mind trends in that regard as well. For instance, there is a large distinct band of category 5 hurricanes that have gone over the southern tip of Florida. I also realized the general horse-shoe trend of hurricane movement, in which most form in the middle of the Atlantic at tropical latitudes, move northwest towards the United States, and then turn northeast to go back out into the ocean.
Conclusion/discussion
It is very important to know about places that have higher risks for things than others. Knowing a place’s hurricane proneness is no exception. People in these places must be very aware of their surroundings and may need to act in the case of an emergency. It is interesting to see this distribution of hurricane paths and frequency across states and relating them to other topics. For example, Palm Beach County, Florida, one of the wealthiest places on the planet, is tied for the highest hurricane frequency in the state. It shares its tie with Monroe County, Florida, which bears the Florida Keys, deemed by many as one of the most relaxing places on Earth. These places are in tropical, coastal, humid environments, the same environments that help bring hurricanes to life. We must be able to prepare for and understand the environments in which we live.
