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Hurricanes & Climate Change – What Do We Know?

How to Prepare for an Extreme Weather Disaster – Tips from a Preparedness Expert

As Global Temperatures continue to rise from Climate Change and Extreme Weather Events are now the new norm, producing more deadly weather patterns, we are more determined than ever to Get Ready Now! And keep an eye on the weather map on this page (it is interactive so you can move to another ocean area).

Get More of the Facts About Climate Change from NASA

What is a Hurricane?


According to the National Oceanic and Atmospheric Association (NOAA), a hurricane (tropical cyclone) begins as a rotating low-pressure weather system that has organized thunderstorms but no fronts (a boundary separating two air masses of different densities – high and low). When a storm’s maximum sustained winds reach 74 mph, it is called a hurricane. Hurricanes are rated on a scale of maximum sustained wind speed from 74 to 157 mph or higher in categories of 1 to 5. The higher the category, the greater the hurricane’s potential for property damage.

What we fear: The awesome power of sustained winds beyond 100 mph presents a lethal potential of entire communities laid waste by the sheer force of those winds and torrential rains against which few of us can stand. A storm with wind speeds of 150 mph and more can shatter windows, rip off a roof, tear homes apart, and even kill us while blowing down trees, power lines and anything else standing in its path. A proposal for a new Category 6 level for storms with sustained winds exceeding 192 mph adds another level of terror to the thought of hunkering down in a vulnerable home through a storm that may last for hours. Sophisticated weather mapping tools can predict storm path and strength days in advance which amplifies the anxiety prior to the storm making landfall. No prediction, however, is 100% certain, and even slight deviations from the forecast can bring catastrophic results. Tracking the storm and heeding all the posted warnings is critical to safety. The message to Get Ready Now has never been more important. Read: How to prepare for a Hurricane.

What we experience: When a hurricane forms and begins to intensify, it may give us a moment’s pause, but when the first Hurricane Watch is posted by a meteorologist, we pay attention. And when the path aims directly for our own area and the first Warning goes up, particularly for coastal communities, people board up windows (plywood is in great demand), tie down anything that might take flight and generally look for safe shelter or in the worst case evacuate as the storm approaches. There is a rush to prepare for those who have done little in advance with a run on local stores for food and household supplies, generators, batteries and bottled water. The scale of the ferocity of winds can be felt in its voice, an incessant, deafening howl of fury that seeks only to destroy. And the storm surge and flooding that follow can often be worse than the winds.  A hurricane is a wind and water disaster in the making, both elements carry death and destruction.

map of Hurricane Delta heading for gulf Coast

As an example of the impact of epic storms in this century — and one of the worst in modern history — Hurricane Katrina struck and inundated the city of New Orleans in 2005, leaving much of the Gulf Coast in ruins. The monstrous storm surges unleashed by Katrina breached levees and left more than 1800 people dead and more than 1 million homeless. Damage was estimated at over $100 billion. Hundreds of health clinics, pharmacies and other health facilities were destroyed. As a result, the death toll number doesn’t capture the indirect deaths caused by factors like displacement, lack of access to healthcare, and mental health issues triggered by the disaster. Americares responded within days and stayed for years in the massive recovery effort.


For decades at Americares, we have seen up close the staggering magnitude of extreme weather losses for families and communities – the personal history and common goods. Access to medicine security and to health services become early casualties as emergency responders rush to provide the basics of food, shelter, clean water and hygiene in the first days. We know that immediate access to primary health services, including mental health support, along with medicines and medical supplies will save lives and restore health. Working with local partners, governments and other nonprofits to meet immediate needs, we then help survivors rebuild health facilities and services and restore hope for the future. No matter where extreme weather disasters strike, we are there and together with our partners, even in the worst times, we can make health happen.

Learn more about health crises from Climate Change: Floods. Extreme Heat. Wildfires.

How Do Hurricanes Form?

Necessary Conditions

Tropical cyclones are like giant engines that use warm, moist air as fuel. That is why they form only over warm ocean waters near the equator. The warm, moist air over the ocean rises upward from near the surface. Because this air moves up and away from the surface, there is less air left near the surface. The warm air rises, causing an area of lower air pressure below. Hurricanes typically require a specific set of conditions.

According to the NOAA and NASA:

  • Hurricanes form by drawing their energy from warm water, and temperatures above 77°F (25°C)
  • A pre-existing low-pressure system, often originating from tropical waves or areas of converging winds, is necessary for the initial development. Low pressure creates an environment where air can begin rising and converging.
  • Lots of moisture in the atmosphere is essential. As warm, moist air rises, it cools and condenses, forming clouds and releasing latent heat. The released heat further fuels the rising air, creating a cycle that strengthens the storm.

How Hurricanes Form Infographic

  • Contrary to what might be expected, in the early stages of formation, strong winds can disrupt the developing storm by shearing it apart. Therefore, relatively light winds, especially in the upper levels of the atmosphere, are necessary for a hurricane to maintain its organized structure and rotation.
  • As the storm system rotates faster and faster, an eye forms in the center. It is very calm and clear in the eye, with very low air pressure. Higher pressure air from above flows down into the eye.
  • Storms that form north of the equator spin counterclockwise. Storms south of the equator spin clockwise. This difference is because of Earth’s rotation on its axis.
Hurricane and tropical storm zones

What Happens After a Hurricane Forms?

Next Levels

The developing storm passes through four stages of formation:

  • Tropical disturbance: A low-pressure system with disorganized showers and thunderstorms forms over warm water.
  • Tropical depression: As the system intensifies, the winds become more organized and reach sustained speeds of at least 39 mph (63 km/h).
  • Tropical storm: With further strengthening, sustained winds reach toward 74 mph (119 km/h) and a well-defined center with a circulation pattern emerges.
  • Hurricane: When sustained winds finally reach 74 mph (119 km/h), the system is officially classified as a hurricane. Hurricanes are classified in five categories by the Saffir-Simpson Hurricane Wind Scale based on their wind speed.
Saffir-Simpson Hurricane Scale

How Does Climate Change Affect Hurricanes?

The Impact

Increased Intensity

  • Warmer ocean temperatures: As the oceans get warmer, hurricanes can become stronger and more intense, reaching higher wind speeds and lower central pressures.
  • More moisture: Warmer air holds more moisture. This means hurricanes can hold more water vapor, leading to heavier rainfall and increased flooding potential.
  • Slower movement: In some cases, climate change may be causing hurricanes to move slower, allowing them to achieve greater strength and inflict damage over a larger area and for a longer duration.

Other Changes

  • Frequency: the overall number of hurricanes may not change significantly, but the proportion of those reaching major (Category 3-5) intensity is likely to increase
  • Storm surge: Rising sea levels due to climate change amplify the threat of storm surge, potentially causing more extensive flooding in coastal areas.
  • Indirect impacts: Climate change can also worsen other factors that contribute to hurricane damage, such as coastal erosion and salinization of freshwater resources.

What Has Changed Already?

  • Stronger storms: Records show an increase in major hurricanes globally since the 1970s.
  • Increased rainfall: Studies have shown that hurricanes produce more rain, leading to devastating floods like those seen in Hurricane Harvey in 2017.
  • Slower movement: Some recent hurricanes, like Hurricane Florence in 2018, have moved slower than average, causing prolonged flooding.
  • Extending the season: The hurricane season officially begins on June 1, and ends on November 30. But as the ocean warms, the season shows signs of beginning earlier and lasting beyond the end of November.

Hurricane Response – Americares on the Frontlines

Our History

Hurricane Response: One of Our Core Principles

On August 29, 2005 Hurricane Katrina struck the Gulf Coast on the Louisiana/Mississippi border and Americares dispatched a response team within 24 hours. Katrina proved to be a major milestone in Americares response and recovery work. To this day, while not the worst hurricane ever to hit the states in recent years, Hurricane Katrina is considered the costliest hurricane in U.S. history. The strength and path of the storm and the devastation it brought to the Gulf Coast followed by required a response on a much larger scale than ever before.

In seven years following Hurricane Katrina, wherever we could make a difference – from child immunization to dental care to mental health support – we helped fill gaps to help people in crisis get the health care they need. It underscored the need for greater access to primary healthcare in the United States. Our support for local health organizations working to meet the needs of storm survivors began a decade of expanding and improving access for people in need to health services in the U.S. Our work included a large scale response to the 2010 Deepwater Horizon oil spill.

Typhoons (Hurricanes in the Pacific) have also intensified with climate change and so-called “Super Typhoons” threaten communities with limited resources to protect their health systems. Super Typhoon Haiyan (2013) – possibly the most powerful storm ever recorded—dealt a massive blow to the Philippines. Torrential rains, 15 foot storm surge and up to 195 mph sustained winds unleashed widespread devastation, power outages and landslides. The storm affected an estimated 16 million people, killed over 6,000, displaced some 4 million and damaged or destroyed as many as 2,000 health centers, hospitals and clinics. It also resulted in heavy damage to other public infrastructure including community centers and schools. We responded and have built a long term presence in the Philippines as a result of its extreme vulnerability to such disasters.


Our Evolving Hurricane Response in the past decade:

The Deadly Year 2017: The historic 2017 Atlantic hurricane season produced 17 named storms, most notably Harvey, Irma, and Maria that left hundreds of dead, destroyed communities across the southern U.S. and Caribbean and caused an estimated $265 billion in damage – the most expensive hurricane season on record. Hurricane Harvey set a new mark for the most rainfall from a U.S. tropical storm (51 inches). Hurricane Irma became one of the strongest Atlantic Ocean hurricanes ever recorded (185 mph winds). Hurricane Maria was the most powerful hurricane to make landfall on the main island of Puerto Rico in 85 years. Hurricane Harvey and Maria are among some of the worst hurricanes in modern history.

Americares simultaneously responded to all three storms, deploying 75 Americares relief workers who spent more than 2,500 days in the field. The teams focused on meeting survivors’ health needs, increasing access to care and preparing safety net health facilities to better prepare for future storms. Our extensive U.S. Program partnerships with a network of local safety net clinics and health centers provide the foundation for the speed of our response and the magnitude and quality of our recovery efforts. Our long-term recovery programming focused on mental health and psychosocial needs, and that has become a bedrock of our response and recovery work.

Our response and recovery work in Latin America has often focused on restoring and rebuilding community health centers that often represent the only access to health care for many people. In 2020, Hurricanes Eta and Iota were devastating Category 4 hurricanes that struck Honduras within two weeks of each other. Together, they killed around 100 Hondurans, and local analysts estimated the damage would cost the country more than 10 billion dollars and leave 2.5 million people with limited or no access to health services due to the hurricane’s impacts. We worked with local partners to change that.


Climate change adds new factors each year such as rising sea levels and increasingly complicated logistics that affect our planning and preparation. As the season lengthens, the areas that are at risk of hurricane strikes continue to expand – see this interactive map in the Washington Post. With each storm, we encounter unique circumstances which is why we say that when a storm strikes, we hit the ground listening.

How to Prepare for a Hurricane

The Danger Season

The Best Response is a Good Plan

Climate change and the resulting extreme weather events create some specific challenges for Americares Emergency Response Team and our healthcare partners, and good planning and prepwork provides response solutions. Building Resilience in the health system as the threats from climate change multiply becomes more and more critical. For example:

  • Wind and water damage to health facilities can render the facility inoperable when it is most needed rendering the facility inoperable when it is most needed. After providing emergency repairs or a temporary facility, restocking medicines/supplies, and replacing equipment, we strive to help the local partners build back better. And beyond repairs, the next step is to help build Climate Resilient Health Centers.
  • Since evacuations to shelters are common in a major storm, relief supplies are assembled and stocked in advance to be ready for quick distribution,
  • Loss of power leads to a loss of medicines that require refrigeration such as insulin and vaccines therefore Solar Power and/or Generators with fuel to run them along with the rapid resupply of lost medicines are critical.
  • Trauma and other extreme stress for survivors including health workers are much in evidence in the immediate aftermath of the storm therefore, in preparation Trained health workers must be available to identify trauma and support programs for those most at risk, and especially support for health workers who are often survivors themselves.
  • Personal Preparedness: Get the Five Steps to Ready and be Prepared for the Next Hurricane:

Other Extreme Storms

Tornadoes and other Threats

Tornadoes

A deadly funnel appears, giving only minutes of warning; the incredible power of the wind vortex in an EF-5 tornado (estimated wind speed of over 200 mph) can literally tear apart anything above ground. Important to pay close attention to your local warning system and to have a safe place to shelter below ground level quickly when a warning is heard. When the threat of tornadoes appears, having a safe shelter readily accessible could save lives. Since tornadoes appear suddenly, the warning signal will only leave a short time to find shelter.

There were nearly 500 tornadoes reported in the first 3 months of 2023, nearly double the average for that time period. The U.S averages 1150 tornadoes per year and “Tornado Alley” has moved eastward from the midwest to southern states with even more deadly potential.

Hurricanes and other severe storm systems can often produce tornado outbreaks sometimes as many as 50 tornadoes across a wide area as happened in 2022 in Kentucky and five other states. As storm systems become more intense with climate change, the likelihood of severe thunderstorms and tornadoes increases. Storm cellars and other protected areas offer the best protection when a tornado appears.

Typhoons

You’ve often heard of Typhoons, but what are they really? What is the difference between a Hurricane and a Typhoon? In terms of their formation, structure, and behavior, hurricanes and typhoons are very similar. They both originate from warm ocean waters and can cause similar levels of destruction when they make landfall. Typhoons are mostly the same phenomenon as hurricanes but originate in the northwestern Pacific Ocean. These storms often impact countries such as Japan, China, the Philippines, and other parts of Southeast Asia.

Hurricane Recovery - The Ramos family searches the rubble of their home
One member of the Ramos family walks through the remnants of their home

As we get ready for the next super storm, we know that we can’t do it without you.

Please help your neighbors near and far with a gift right now.

Our Work:
Responding to Extreme Weather and Other Disasters