Hurricanes are low-pressure systems that form over warm ocean water and result in intense thunderstorm activity. A low-pressure system refers to an area where the air pressure is lower than its surroundings. This low pressure causes air to be sucked into the center, which, in turn, draws stronger winds toward the low-pressure area and may result in a storm.
Hurricanes are characterized by strong wind speeds, dangerously high water, and rough seas. A single hurricane can produce raging winds of about half as much energy as the electrical generating capacity of the entire world. Typical hurricanes are about 300 miles wide, although they can vary considerably in size. Interestingly, the size of a hurricane may not always determine its intensity. An example is Hurricane Andrew of 1992, which was the second most devastating hurricane in US history, despite its relatively small size.
Hurricanes form over warm ocean waters near the equator and often begin as tropical waves. Not all hurricanes make landfall. A hurricane or tropical cyclone is said to make landfall when the storm's center crosses a coastline. There are three main conditions for a hurricane to form:
A hurricane has three main parts: the eye, the eyewall, and the rainbands. The eye of a hurricane refers to the hurricane's center, a relatively calm, clear area of sinking air. It is also made up of light winds that usually do not exceed 15 mph with a width of 20-40 miles. The air in a tropical cyclone moves towards the eye, and this causes the wind speed to increase.
The closest to the center that strong winds can reach is called the eyewall. This part of a hurricane has the strongest winds. The eyewall consists of a ring of tall thunderstorms that produce heavy rains. Meanwhile, rainbands are curved bands of clouds and thunderstorms that trail away from the eyewall in a spiral fashion. Rainbands are often responsible for producing powerful bursts of rain, winds, and, sometimes, tornadoes.
The first stage is the formation of a tropical wave. At this stage, water vapor is released and rises into the atmosphere from the warm oceans. As this hot air rises, it condenses into water droplets and forms dense vertical clouds in the lower troposphere. Larger and higher cloud columns are made from continuous evaporation and condensation.
These columns eventually form a pattern, and wind circulation around their center causes warm air to encounter more clouds. This movement creates a cluster of thunderstorm clouds, i.e., a tropical disturbance. The cooling of the water vapor at the top of the cloud column releases heat energy making the column unstable.
The heat increases the air pressure and causes winds to move away from the high-pressure area. This movement has a reverse effect on the surface as it causes the air pressure to drop. Then, air moves towards the lower pressure area and creates more thunderstorms. The winds in the storm cloud column begin to pick up speed as they rotate in a circular motion around the calm center of the storm. The storm officially becomes a hurricane when wind speeds reach 74 mph. Hurricanes are stronger on the sea due to the energy from the warm ocean waters.
Hurricanes are categorized into different classes based on wind speed. The Saffir-Simpson Hurricane Wind Scale is a 1 - 5 rating based on a hurricane's maximum sustained wind speed. This scale does not consider other potentially deadly hazards such as storm surges, rainfall flooding, and tornadoes.
The different categories cause varying damage, with devastating damage beginning from category 3 hurricanes where wind speeds exceed 111 mph. Likewise, category 4 and 5 hurricanes can be catastrophic, and the latter will make the area uninhabitable for weeks or possibly months. Both categories have wind speeds reaching up to 157 mph. Hurricane Katrina, one of the worst hurricanes in United States history, became a category 5 hurricane when it peaked at 175 mph during the hurricane season of 2005. The hurricane made a second landfall in Louisiana as a category 3.
Hurricane season in South Carolina is between June 1 and November 30 every year. Hurricane season is the distinct period of the year when hurricanes are most likely to develop and occur in a given place. According to the National Hurricane Center and Central Pacific Hurricane Center, there are two major hurricane seasons based on where they occur. There are the Atlantic and Eastern Pacific Hurricane Seasons.
The Atlantic hurricane season spans between June 1 and November 30, and hurricanes form in the Atlantic basin area. The Atlantic basin area includes the Atlantic Ocean, the Gulf of Mexico, and the Caribbean sea. The first major hurricane in this season usually forms in late August or early September. On the other hand, the Eastern Pacific hurricane season runs from May 15 to November 30 and extends westwards from Central America and Mexico.
Hurricanes or other tropical systems can have five major impacts: wind, flooding, storm surge, rip currents, and tornadoes. These occurrences can have serious consequences on the environment, infrastructure, and vehicles.
Wind. Hurricanes produce violent winds, and varying wind speeds can cause varying levels of damage. From moderate levels, where mobile homes and poorly constructed buildings may be affected, to more extreme levels, that destroy well-constructed infrastructure, winds constitute a real threat during severe storms.
People, pets, and livestock exposed to the winds are at significant risk for injury or death. The size of a tropical cyclone wind field can expand out hundreds of miles from the storm's center, with the concentration of strongest winds usually located in the eyewall.
Flooding. Another part of a hurricane that may cause significant damage is flooding. Tropical cyclones often produce widespread, torrential rains over 6 inches, which may result in deadly and destructive floods. Inland flooding is the biggest threat to people during a hurricane because it directly damages buildings, washes away roadways, and causes drowning.
In addition to the risk of drowning, floodwater can contain harmful household, medical, and industrial waste.
Storm Surges. Storm surges are another devastating feature of hurricanes. The estuaries and coastal areas are the most vulnerable areas during a storm surge. These areas are at risk because storm surges expose coastal areas and residents to injuries and property damage. A storm surge can also ravage roadways, railways, ridges, and ports, thereby affecting transportation and delaying relief response to those areas.
Rip Currents. Other accompanying events of a hurricane are rip currents and tornadoes. A rip current is a strong, localized, and narrow current of water that moves directly away from the shore toward the ocean at an acute angle to the shoreline.
A person caught in a rip can quickly be swept away from shore. All six casualties in 2009 in the US, directly attributable to tropical cyclones, resulted from drowning from large waves or strong rip currents.
Tornadoes. Hurricane-induced tornadoes can also be expected during tropical activity. Tornadoes are formed in the outer rainbands, which can be hundreds of miles away from the storm's center. Usually, tornadoes produced by tropical cyclones are relatively weak and short-lived, but they still pose a significant threat.
South Carolina is one of the most hurricane-ravaged states in the country, with every part of the state susceptible to hurricane disasters. This is because of the state's proximity to the ocean. South Carolina has a 79.7 chance of being impacted by a tropical system each year, according to the South Carolina Department of Natural Resources.
About 44 tropical cyclones made landfall along the state's coastline between 1851 and 2021. Only four of those have exceeded category 3: the Sea Islands Hurricane in 1893, Hurricane Hazel in 1954, Hurricane Gracie in 1959, and Hurricane Hugo in 1989.
The spread of coastal and low-lying areas makes the state more vulnerable to hurricanes. Inland areas are also not spared from severe storms and often experience their fair share of tropical activity yearly.
Particularly, the inland areas in central South Carolina are vulnerable to flooding, high winds, and even tornadoes. All of these, including storm surges, can also affect the coastal areas in the state. During hurricane season, peak tropical activity in South Carolina occurs between mid-August and late September. There has been no record of a hurricane making landfall in the state after October 31.
There have been numerous hurricanes in the history of the state. One of them was Hurricane Hugo in September 1989. Hugo peaked as a rare Category 4 hurricane and is regarded as one of the strongest hurricanes in South Carolina history. Wind gusts as high as 108 mph were measured in the city of Charleston, while Winyah bay in Georgetown county recorded sustained winds of 120 mph.
The hurricane traveled so far inland that it reached regions that typically never see such severe storms—it was located halfway between Charleston and Sumter, SC. The disaster resulted in 86 fatalities and an estimated $10 billion in property and infrastructure damage. Hugo's destruction extended beyond South Carolina to the Caribbean Islands of Guadeloupe, St. Croix, and Puerto Rico.
The second costliest hurricane in US history, Hurricane Charley (August 9 - 15, 2004), although mostly limited to the state of Florida, also affected parts of South Carolina. The damage from the storm is estimated to be up to $15 billion. Fortunately, casualties were low, with only ten deaths in the US. After passing through Florida, Hurricane Charley came ashore again near Cape Romain, South Carolina, near midday on the 14th as a category 1 hurricane. Charley made a final landfall in North Myrtle Beach before weakening to a tropical storm over southeastern North Carolina.
Hurricane preparedness in South Carolina mainly involves personal preparations to secure loved ones and property and looking out for warnings or alerts.
There are two major types of alerts that may be issued: hurricane watch or hurricane warning. The National Hurricane Center issues these alerts based on the projected time until landfall.
A watch means hurricane conditions pose a possible threat in a specified region within 36 hours of issue. Residents must begin preliminary preparations and wait for further directives.
Meanwhile, a warning is more serious than a watch, and preparation should have been completed by this time. Storms can be expected within 24 hours after a hurricane warning is issued.
The Federal Emergency Management Agency (FEMA), the Federal Communication Commission (FCC), and the National Weather Service (NWS) coordinate the national public warning system. There are two important alert systems, which are:
1. The Emergency Alert System (EAS): states and local authorities use this system to deliver important emergency information, such as weather and AMBER alerts. It also allows the president to address the nation within 10 minutes during a national emergency.
2. The Wireless Emergency Alerts (WEAs): short emergency messages from authorized federal, state, local, tribal and territorial public alerting authorities that can be broadcast from cell towers to any WEA‐enabled mobile device in a municipality. Some examples of these are imminent threat alerts and public safety alerts.
Dealing with a hurricane disaster can be challenging. What makes it easier is making proper preparations to ensure the safety of lives and property in advance. The best time to prepare for a hurricane is before the season begins.
Weather watches and warnings will usually be issued before a hurricane hits. Local emergency managers will provide the latest recommendations based on the threat posed and appropriate safety measures from state, local and territorial agencies.
One sure step to avoiding the worst of a hurricane is by drawing up an emergency plan. The plan should be drawn up and rehearsed with family members so everyone knows what to do during an emergency. It should include support and assistance to family members with chronic illnesses, disabilities, and pets.
It is very important to ensure that homes, office buildings, and other structures are well-equipped to withstand damage from hurricanes. Structural repairs, if necessary, should be made to the buildings.
Furthermore, windows and doors should be boarded up and secured with proper materials to avoid damage from flying debris. Trim trees to prevent damage from broken branches. Bring in outdoor equipment like lawn furniture and outdoor grills to prevent them from being flung around during the storm.
Move cars, trucks, and boats into the garage or other secure locations to prevent them from getting destroyed. Also, fill up vehicle gas tanks and keep emergency kits in the vehicle when making plans to evacuate.
It is advisable to stock up on food, water, and medicine when preparing for a hurricane. Remember to make extra provisions for family members and pets with special needs. Also, follow health guidelines, such as getting vaccinated for COVID-19, hand sanitizers, face masks, and test kits if unvaccinated.
Ensure that cell phones and other electronic devices are well charged in preparation for a storm. Backup charging devices may also be used to power electronic appliances. It may become necessary to turn off the power, especially during flooding. Additionally, the contact information for emergency services (such as the hospital or police) and family members should be made easily accessible.
Keep documents containing sensitive information in water-proof bags and store them in secure locations. It may also be helpful to make copies of the documents and store the originals off-site. Also, consider keeping copies in secure, password-protected cloud-storage services.
Due to the financial risk posed, it is useful to have comprehensive insurance coverage for reinstating damaged property. In preparing for a hurricane, policyholders should review their insurance policies to ensure that damage from weather disasters is covered. The National Flood Insurance Program (NFIP) offers flood insurance and provides helpful resources on obtaining good flood insurance coverage.
The Federal Emergency Management Agency (FEMA) provides guidelines for individuals and communities to construct safe rooms to remain safe through severe weather conditions. A safe room is a hardened structure designed to meet FEMA criteria and provide near-absolute protection in extreme wind events, including tornadoes and hurricanes.
When advised to evacuate, do so promptly. Do not ignore an evacuation order. And before evacuating your home, switch off appliances, and turn off the gas, electricity, and water. Train children and pets on locating the evacuation zone in case they get separated during the storm. It may also be helpful to communicate evacuation plans with relations outside the storm's path.
An emergency supply kit containing adequate supplies should be packed and ready to go when evacuating. Additionally, important documents such as insurance policies, medical information, and emergency contact information should be carried along when evacuating.
During an evacuation, remember never to drive or attempt to swim through a flooded area, as vehicles can be swept away or stalled in moving water. Moving water may also have harmful rodents like snakes or debris and objects that can cause injury or illness. Wear protective gear such as rubber boots and goggles if entering floodwater is the last resort.
Experts and anecdotal evidence suggest sheltering as one of the prime ways to stay safe during a hurricane.
A hurricane shelter refers to a place designated as a safe refuge during a storm or hurricane. Sheltering is the act of seeking protection from severe weather occurrences in a place considered safe. During a hurricane, affected persons should endeavor to take refuge in a designated shelter or an interior room for high winds.
Sheltering options include mass care shelters, staying-at-home, and sheltering-in-place shelters. A mass care shelter provides facilities and supplies like food and water to survivors. Staying-at-home shelters involve remaining in the home throughout severe storms and limiting outdoor activities. It may be safe to shelter in the home when permitted by the authorities, and non-major hurricanes are expected.
Meanwhile, it is advisable for individuals to shelter in place when there is uncertainty about the situation outside. This option is temporary, and it is important to pay attention to emergency broadcasts to determine the next best course of action.
When sheltering-in-place, it is advisable to go to the highest level of a building when trapped by flooding. Do not attempt to climb into a closed attic due to the danger of being trapped by rising flood water. Additionally, accessible exits should be built into a hurricane shelter for emergency exits to avoid people getting trapped during the hurricane.
The American Red Cross provides disaster shelters in different local communities based on local emergency plans and the scale of the disaster. These open shelters, as well as maps to locate them, are made available to individuals who have been forced to evacuate due to an imminent disaster such as a hurricane. These shelters may even provide for pets to be housed in a different location when it is not convenient to house them in the open shelter.
After a hurricane has blown over, survivors should remain careful and continue to follow directives. Imperatively, evacuees should avoid returning to affected areas before it is declared safe to do so by the authorities. Accidents may still occur after a hurricane has passed due to such occurrences as flash floods.
To ensure safety, continue to listen to local radio and adequately follow government-issued directives. Persons returning to storm-damaged areas should look out for downed electrical wires, fallen objects, and weakened structures that are prone to collapse. It may be necessary to bring supplies along or drive out of that zone to get supplies. This is because it may be unsafe to consume food or water in that zone for the period immediately after the disaster.
Upon returning home, do a damage assessment by inspecting for loose power lines, gas leaks, and structural damage. Hurricanes can damage buildings and make them unsafe. Avoid entering damaged buildings until local authorities determine it is safe.
Make sure to document hurricane damage with photographs and reach out soon enough to the insurance company when a property has been damaged during the disaster. The Charleston government provides a damage reporting tool available to the public.
During clean up, wear protective clothing and work with somebody else. Avoid touching wet electrical appliances. Turn off electricity at the main breaker or fuse box to prevent electrical accidents.
Children should not be allowed to assist in cleaning up after a hurricane. Homes should be cleaned and aired out by opening doors and windows after the storm or flood ends.
Power outages are normal during and after hurricanes. If portable generators are to be used, they should be installed outdoors. Individuals may suffer from carbon monoxide poisoning from generators when used indoors or in the garage, which can be fatal.
There are state resources made available to residents who have suffered hurricane damage. The South Carolina Office of Resilience helps with Housing recovery for federally declared disasters, mitigation against future flood risks, and resilience planning. Another state resource is the SCEMD which provides individual and public assistance to assist citizens during the short, intermediate and long-term phases of recovery. The Federal Emergency Management Agency (FEMA) also provides disaster assistance to victims of hurricanes.