Hurricanes of the American South

July 17, 2023
6-9 minutes


Hurricanes are some of the most well known extreme weather phenomena, and for good reason—they can inflict widespread catastrophic destruction, often  billions of dollars in damages, as well as claiming the lives of those who are hit the hardest. Hurricanes also have the capability to destroy infrastructure and leave huge populations without power for weeks, leaving large metropolitan areas struggling to rebuild their cities in the aftermath.  In the United States, certain Southeastern areas are prone to these mega storms due to the warm waters that exist off of their coasts, leaving them vulnerable to sustain the worst these cyclones have to offer. Additionally, climate change is threatening to worsen the severity of individual hurricanes, posing a massive problem for the future if the US hopes to ever develop systems capable of mitigating the damage.

What is a hurricane?

A hurricane is a powerful and often destructive tropical cyclone that typically forms over the warm waters of the equator in the Atlantic Ocean, Caribbean Sea, and central and northeastern Pacific Ocean. These storms often begin as tropical waves—low pressure areas that are blown westward across the tropics by trade winds. As they move along these moisture-rich environments, warm ocean air rises upward away from the surface where it begins to cool, forming clouds. As more clouds form, Earth's Coriolis Effect causes the wind and clouds to start to spin, creating an eye wall with a center that is low pressure because all the air keeps rising out and away from the area.

The term “tropical cyclone” refers to any storm of this nature—one that originates as a low-pressure area over warm waters, and becomes a rotating, organized system of clouds and thunderstorms. However, scientists have split up types of tropical cyclones into four categories to denote their level of extremity: tropical disturbances, tropical depressions, tropical storms, and finally, hurricanes. A storm is only classified as a hurricane once its winds have reached 74 mph, at which point it is more than 15,000 meters high and nearly 200 kilometers across. These conditions bring strong winds, heavy rainfall, storm surges and can even trigger tornadoes when the storm makes landfall.

Hurricanes also have varying degrees of severity. Using a scale known as the Saffir-Simpson Hurricane Wind Scale, each storm is given a designation from 1-5 based on their wind speed and potential to cause damage, which ranges from “minimal” to “catastrophic.” The strong winds can tear apart buildings, uproot trees, and cause widespread power outages, sometimes lasting for days or even weeks. The winds can also create storm surges—abnormal rises in sea level that can flood coastal areas—and heavy rainfall can cause flash floods and landslides, all of which can devastate infrastructure.

Where do hurricanes occur in the United States? Why?

Hurricanes form in five major “basins” around the world: the Atlantic, Eastern Pacific, Northern Pacific, Southern Pacific, and Indian Oceans, though some these basins are much more active than others. In the United States, areas along the Gulf and Southeast Atlantic border are most affected, including states such as Texas, Mississippi, Alabama, Louisiana, and most notably in recent months, Florida. Because they are affected by hurricanes occurring in the Atlantic basin, hurricane season stretches between the months of June and November, during which 97% of all recorded cyclones in the region occur.

These specific areas are most affected due to the necessity of warm water in order for hurricanes to form. The water in the Gulf and in the Western regions of the Atlantic Ocean provide this warm water, particularly between mid-August and late October when the conditions are most favorable to the creation of cyclones. The warm and moist air coming from the water also combines with the atmospheric instability of the region that promotes the rapid upward movement of air, and further develops and intensifies the storms.

Geographical features of the Gulf and Southeast Atlantic coastline, such as shallow waters and the Loop Current (a current that curves through Cuba, the Gulf and the Florida Straits), also add fuel to hurricanes. These areas also have coastlines littered with bays, inlets, and low-lying coastal areas, all characteristics that can enhance the impact of storm surges, and therefore the harm hurricanes can inflict.

Other areas of the US are also affected by hurricanes, but sustain considerably less damage much less frequently. Storms affecting states further North up the East Coast such as Virginia and the Carolinas are generally less powerful after traveling so far over land and thus losing their energy source of warm ocean waters. Additionally, though warm air masses develop in the Pacific Ocean and make landfall on the West Coast, they rarely have the same severity they do in the Southeast. However, that is not to say that devastating hurricanes are not possible outside of the Southeast. For example, only a decade ago in 2012, Category 3 Hurricane Sandy hit New York City, ultimately causing an estimated $19 billion USD in damages, killing 44 residents, and displacing thousands more.

Why are hurricanes getting worse?

Climate change is exacerbating hurricanes in a multitude of ways, making them much stronger and therefore inflicting more devastation on the area they hit. Firstly, most scientific weather models predict that hurricanes in the future will have higher wind intensity. As the oceans warm, they will provide more energy and moisture to contribute to the formation of hurricanes. These warmer waters increase the rate of intensification of these storms, allowing them to strengthen more in shorter periods of time. Though these models do not predict an increase in the frequency of hurricanes, they do predict that warmer oceans will result in a greater proportion of hurricanes reaching higher classifications on the Saffir-Simpson Scale, with stronger winds and therefore the ability to inflict greater damage.

Additionally, climate change can also lead to changes in precipitation patterns. At warmer temperatures, air can hold more water vapor. The increased amount of moisture in the air contributes to storms having heavier rainfall when they come ashore, increasing the risk of flooding. More rain, paired with rising sea levels on account of the warming climate, pose a significant threat to to coastal towns, as a higher sea level can exacerbate the impact of storm surges and allow them to penetrate further inland.

Finally, climate change also has the potential to alter atmospheric conditions and patterns, which greatly affects hurricane movement. Changes to atmospheric circulation can influence the paths of storms, leading them to impact regions that are not historically prone to such storms and therefore do not have the necessary infrastructure or response systems in place to deal with the damage inflicted.

Case Study: Hurricane Harvey

Hurricane Harvey was a long-lasting tropical depression storm that eventually gained strength in the Gulf of Mexico and made landfall on August 25, 2017 in Rockfort, Texas. Prior to hitting the US, the hurricane passed over Barbados and St. Vincent before ultimately strengthening into a devastating Category 4 storm, the first of its kind to reach Texas since hurricane Celia in 1970. The storm decimated coastal areas of Texas with its 210-kph winds and 1.8-meter storm surge, as well as thunderstorms and tornadoes that caused widespread devastation. Though the storm was downgraded back down to a tropical storm within a few days, it continued to linger over Texas, ultimately dumping a US-record 130 cm of rain and 27 trillion total gallons of water over the state. The high levels of rain, combined with the hurricane's storm surge, caused catastrophic flooding in the Houston metropolitan area and Southeast Texas. The effects killed dozens, destroyed almost 180,000 houses, left as many as 30,000 people without shelter, and inflicted an estimated $125 billion USD in damages to homes, buildings, vehicles and basic infrastructure. The storm also was responsible for hundreds of millions of dollars in damages to Texas crops and livestock, and the coastal tourism industry was also majorly impacted. Destruction of structures and equipment and ensuing power outages also significantly affected a variety of other economic sectors, including manufacturing, energy, chemical production and retail sales. The flooding also majorly impacted the ability of workers to get to work, majorly disrupting the flow of goods. In order to prevent the far-reaching effects of hurricanes in the future, the city of Houston and surrounding counties have taken steps to become more resilient to extreme storms. Initiatives include turning to greener infrastructure solutions such as converting neighborhood parks into stormwater detention basins, building rain gardens, buying out properties in flood plains and building more flood resilient multi-family apartments.

Case Study: Hurricane Ian

Hurricane Ian was the fifth-strongest storm to ever strike the United States when it made landfall on September 28, 2021, and also the strongest hurricane to cross the Caribbean in September since 2007. It first entered Coloma, Cuba on September 27, and used the warm waters in the area as fuel to eventually grow into a Category 5 storm. The hurricane, at that point a Category 4, then struck Caya Costa, Florida on September 28 with winds of around 240 kph and a storm surge as high as 4 meters in some places, penetrating several miles inland. Most cities and towns in its path experienced rainfall between 25-50 cm, designating it a once-in-1,000 years rainfall event. High amounts of rain, coupled with an enormous storm surge led to flash flooding stretching as far north as Palm Coast, Florida. After weakening considerably in its time over land, the hurricane then re-entered the Atlantic and rose again into a Category 1, which hit South Carolina on September 29 before eventually dissipating for good. The hurricane caused an estimated $113 billion USD in properties and infrastructure damages, killed about 160 people, and destroyed 8,000 homes in Florida alone. It also left millions without power, with hundreds of thousands still offline almost a week after the hurricane dissipated. The storm surge was catastrophic: some reports suggest 97% of all buildings in Fort Myers beach were either impaired or destroyed, while many were completely pushed off their foundations. Extensive damage was also sustained along roads in coastal areas, crippling rescue efforts and inhibiting employees from returning to work in the aftermath. Many engineers and urban planners noted that older Florida property codes that were not designed specifically to sustain wind and increased rainfall accounted for most of the damages, as building collapses led to growing and injuries. Instead, engineers suggested the use of “sacrificial floors” that allow water to pass through buildings' lower floors without threatening collapse.  In the aftermath, experts also called for better hurricane evacuation warnings for citizens in order to get them out of harm's way and minimize loss of life. A study following Hurricane Ian cited global warming as a contributor to Hurricane Ian's huge rainfall, suggesting that over 10% of the rainfall could be associated with warming temperatures that allowed it to pick up more water in its approach to Florida.

How can HD Rain help Mitigate Hurricane Devastation?

HD Rain's sensors provide high-resolution weather data—an accuracy of 500 square meters, minute by minute iterations and up to 2 hours forecast—that is extremely helpful during instances of extreme weather. Firstly, they can keep the population well-informed about weather conditions both in real time and before they occur, which can help citizens better protect themselves from the danger that hurricanes pose. HD Rain also partners with public safety organizations in order to maximize the efficacy that these groups have in saving lives. For example, because HD Rain's technology can evaluate the variation in rainfall intensity and accumulation between different areas, they can partner with fire departments and coast guards to help them coordinate search and rescue efforts and more accurately delegate aid to the towns that need it most. Additionally, HD Rain's forecasting capability can even allow them to assist local governments in identifying when to tell residents to evacuate before storms hit — minimizing injuries and saving lives.


Hurricanes are an extreme weather event that pose great danger to the populated areas they strike, and a rapidly warming climate promises to increase the severity of these storms. The Southeastern Atlantic coast of the US, particularly Florida, faces these dangers, as it situated in an area that sustains dozens of cyclones each year. Thus, it is incredibly important for governments, businesses, and every day citizens to steps to minimize climate effects to try to limit the strength of these storms. Additionally, it is important for all areas that lie within the potential path of hurricanes to implement infrastructural changes that can better handle the strong winds, heavy rainfall, and storm surges that threaten their populations. It is vital that citizens be prepared ahead of time: by having better warning systems, as well as a set plan in place in the case of disaster, residents can help protect themselves, their families, and their property from the potential damage caused by these storms.