All About Hurricanes

Welcome to “All About Hurricanes” our master guide to these destructive severe weather events.

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What is a Hurricane?

If you’re just learning about hurricanes, the most basic question you can ask is: “What is a hurricane?” Even people who think they know a lot about these forms of severe weather might not know exactly what a hurricane is. That’s why we’ll share the National Oceanic and Atmospheric Administration’s definition of hurricanes.

Hurricane Definition: A tropical cyclone, or low-pressure weather system with organization thunderstorms but no fronts, with maximum sustained winds of 74 mph or higher.

These are very violent storms with dangerous weather conditions like:

Red hurricane / cyclone icon High winds

Red hurricane / cyclone icon Heavy rainfall

Red hurricane / cyclone icon Storm surge

Red hurricane / cyclone icon Flooding

Red hurricane / cyclone icon Rip currents

Red hurricane / cyclone icon Tornadoes

How Do Hurricanes Form?

There are a few factors that can cause a hurricane to form. According to NASA there are four main ingredients that combine to make a hurricane.

The first is a pre-existing weather disturbance. Most hurricanes start as a tropical wave, or low-pressure area.

The second ingredient is warm water. As the tropical wave moves through moisture-rich tropics, thunderstorm and shower activity increases. Warm water and air are the fuel that powers hurricanes. As warm ocean air rises into the storm, it cools and causes thunderstorms.

Thunderstorms are the third ingredient to any hurricane. These turn ocean heat into “hurricane fuel” as NASA calls it.

Finally, hurricanes need wind. Low-wind shear, to be exact. A large difference in wind speed and direction around or near the storm can weaken it.

These four conditions are necessary for hurricane development but their presence doesn’t guarantee hurricane formation.

Where do Hurricanes Form?

A red map of the world over a grey circle backgroundSince hurricanes need a few different factors to form, they can only form in certain areas of the world.

Hurricanes are tropical cyclones that form over the Atlantic Ocean or eastern Pacific Ocean. They typically form in tropical waters just north of or south of the equator, where waters are warm.

In the Atlantic hurricane basin, these storms typically start with a disturbance off the West coast of Africa. Also referred to as the North Atlantic basin, this region includes the North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico.

Many people also ask when hurricanes form. Hurricanes typically form during hurricane season.

There are different seasons for Atlantic and Pacific hurricanes. The Atlantic hurricane season stretches from June 1 to November 30. The peak of hurricane season typically happens in September. The Eastern Pacific hurricane season begins May 15 and ends November 30.

Where do Hurricanes Hit the Most?

A small red palm tree and house on apiece of land being blow by the wind to the right. Grey circle in the backgroundHurricanes wouldn’t be such a big deal if they didn’t hit land. Once a hurricane makes landfall, all those on land are subject to its many dangers like storm surge and flooding. The Caribbean, Atlantic coastal areas, and Gulf of Mexico coastal areas are at risk each year. While these areas are all at risk, there are certain regions that see more hurricanes than others.

No other U.S. state sees as many hurricanes as Florida. According to NOAA, 40% of all hurricane landfalls strike Florida. In fact, Florida has seen 117 direct hits by hurricanes in recorded history. After Florida, hurricanes hit the most in Texas, Louisiana, and North Carolina. Outside of the contiguous U.S., areas in the northern Caribbean like Bermuda, the Bahamas, Cuba, Puerto Rico, Haiti, the Dominican Republic, and the U.S. Virgin Islands as well as Mexico also see their fair share of hurricanes.

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Hurricane Strength

Since you understand what hurricanes are it’s important you understand that not all hurricanes carry the same risks. Some are much stronger than others. While all are dangerous, there is a big difference between a Category 1 and a Category 5 hurricane.

In this section, we‘ll go over hurricane strength, the Saffir-Simpson Hurricane Wind Scale, and the differences between tropical disturbances, tropical storms, and hurricanes.

Tropical Categories

A skinny red lightning bolt over a grey circleBefore a storm becomes a hurricane, it is first a tropical depression or a tropical storm. It can also downgrade to these two storms after being a hurricane.

A tropical depression forms when a low pressure area is accompanied by thunderstorms that produce a circular wind flow with maximum sustained winds below 39 mph.

A tropical storm occurs when cyclonic circulation becomes more organized and maximum sustained winds are between 39 and 73 mph.

Hurricane Categories

To help people, businesses, and governments prepare for hurricanes, meteorologists use categories to set expectations for the extent of a storm’s impact.

According to the Saffir-Simpson Hurricane Wind Scale, there are five different categories (1-5).

We consider Category 3, 4, and 5 hurricanes major hurricanes. We call them major hurricanes because of their potential for significant loss of life and damage. It’s important to note that Category 1 and Category 2 storms are still very dangerous and can cause loss of life.

Dark blue "1" in a grey circleCategory 1 Hurricanes

Category 1 hurricanes have sustained wind speeds of 74-95 mph. These are very dangerous winds that can produce some damage.

Well-constructed frame homes could have damage to roof, shingles, vinyl siding, and gutters. Large branches of trees will snap and shallowly rooted trees may be toppled. Extensive damage to power lines and poles that will result in power outages that could last a few to several days.

a dark blue "2" in a grey circleCategory 2 Hurricanes

Category 2 hurricanes have sustained wind speeds of 96-110 mph. These extremely dangerous winds will cause extensive damage.

Well-constructed frame homes could sustain major roof and siding damage. Many shallowly rooted trees will be snapped or uprooted and block numerous roads. Near-total power loss is expected with outages that could last from several days to weeks.

a dark blue "3" in a grey circleCategory 3 Hurricanes

Category 3 hurricanes have sustained winds of 111-129 mph. These winds and associated conditions will produce devastating damage.

Well-built framed homes may incur major damage or removal of roof decking and gable ends. Many trees will be snapped or uprooted, blocking numerous roads. Electricity and water will be unavailable for several days to weeks after the storm passes.

a dark blue "4" in a grey circleCategory 4 Hurricanes

Category 4 hurricanes have sustained wind of 130-156 mph. During Category 4 storms catastrophic damage will occur.

Well-built framed homes can sustain severe damage with loss of most of the roof structure and/or some exterior walls. Most trees will be snapped or uprooted and power poles downed. Fallen trees and power poles will isolate residential areas. Power outages will last weeks to possibly months. Most of the area will be uninhabitable for weeks or months.

a dark blue "5" in a grey circleCategory 5 Hurricanes

Category 5 hurricanes have sustained winds of 157+ mph. These hurricanes are the strongest on the Saffir-Simpson Hurricane Wind Scale. Catastrophic damage will occur during Category 5 storms.

A high percentage of framed homes will be destroyed, with total roof failure and wall collapse. Fallen trees and power poles will isolate residential areas. Power outages will last for weeks to possibly months. Most of the area will be uninhabitable for weeks or months.

How Many Category 5 Hurricanes Have Hit the U.S.?

A red stick person with their left arm under their chin so they look like they're thinkingWhile all hurricanes are dangerous to those in their paths, people tend to focus on Category 5 hurricanes since they are at the top of the scale.

Many people ask how many Category 5 hurricanes have hit the U.S. or made landfall in the U.S. While 34 Category 5 storms are on record in the Atlantic basin, the number making landfall is quite small. Remember, the Atlantic hurricane basin comprises of the North Atlantic Ocean, the Caribbean Sea, and the Gulf of Mexico.

Only four Category 5 storms have made landfall in the U.S.

A dark blue "1" in a red circle “Labor Day” Hurricane (1935)

A dark blue "2" in a red circle Camille (1969)

Andrew (1992)

A dark blue "4" in a red circle Michael (2018)

While these storms were Category 5 when they made landfall, none of them are considered the deadliest or most destructive in history. You can jump to our list of the five deadliest hurricanes to find out more.

Hurricane Naming

As you can see from this list, we didn’t always name tropical storms. Until the early 1950s, forecasters tracked hurricanes by the year and the order the storms occured. Over time this practice grew confusing, especially when multiple storms churned at the same time.

In 1953 the United States began using female names for storms. They later incorporated male names in 1978 to identify Northern Pacific Storms. It wasn’t until 1979 that the U.S. began using names for storms in the Atlantic basin.

How do we decide which names to use? The World Meteorological Organization has a strict procedure. For Atlantic hurricanes there is a list of male and female names which are used on a six-year rotation. The only time that changes is when a storm is extremely deadly or costly. Then that name is retired. In the event that 21 named tropical cyclones occur in a season, any additional storms will take names from the Greek alphabet.

Revisiting Categories

Hurricane Katrina, Hurricane Sandy, Hurricane Florence, and other low category hurricanes that caused a lot of destruction once they made landfall prove hurricane categories can be a little deceiving.

That’s why our meteorologists always explain the grave possibilities for every tropical storm. Wind isn’t the only condition that can cause damage and loss of life. In fact, flooding because of storm surge and high rain rates are more deadly during hurricanes.

Our meteorologist, Mark Ellinwood, believes the Saffir-Simpson Wind Scale might need some updating. You can read his entire argument, but basically he believes that meteorologists need to stress the impacts beyond the category and winds of a hurricane and reorder the messaging to start with safety first.

Hurricane Dangers

A red icon with a house and car underwaterHow dangerous are hurricanes? Hurricanes are one of the most dangerous weather events because there are so many risks that come along with them.

Flooding causes a lot of damage and dangerous conditions for people on the ground. During a hurricane flooding happens for a number of reasons. One of those reasons is storm surge.

Storm surge is an abnormal rise of water generated by a storm’s winds. Storm surge can reach heights well over 20 feet and can span hundreds of miles of coastline.

When the astronomical tide and storm surge come in at the same time, we call that a storm tide.

According to NOAA, the destructive power of storm surge and large battering waves can result in loss of life, buildings destroyed, beach and dune erosion, and road and bridge damage along the coast. Storm surge can also travel several miles inland.

Another hurricane danger that contributes to flooding – even inland – is heavy rainfall. Tropical storms often produce widespread, torrential rains in excess of 6 inches. This can be a lot more when a storm sits in one spot like Hurricane Harvey did in 2017. Some storms just have more rain than others. In 2018, Hurricane Florence dumped 30 inches of rain in North Carolina. With all this rain fall flash flooding can occur quickly.

Dangers Besides Flooding

Besides high winds, storm surge, and heavy rainfall, rip currents are another hurricane danger that affect humans. The strong winds of a tropical storm or hurricane can cause dangerous waves that pose a significant hazard to people at sea and those on the coast.

When waves break along the coast, they can produce deadly rip currents. Rip currents are channeled currents of water flowing away from shore that can pull even the strongest swimmers out to sea. Storms can be over 1,000 miles away and still create dangerous rip currents, so it’s important to be vigilant if you are swimming in the ocean as a storm churns out at sea.

The last main immediate danger hurricanes bring are tornadoes. Hurricanes can produce tornadoes thanks to the thunderstorms embedded in rain bands well away from the center of the hurricane and in the eyewall, alike. The good thing about tornadoes during hurricanes is that these tornadoes are typically weak and short-lived. That doesn’t mean they aren’t dangerous, they just aren’t at the top of the risk.

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Hurricane Safety and Preparation

According to the National Hurricane Center, two keys to weather safety are to prepare for the risks and act on those preparations when alerted by emergency officials.

How to Prepare for a Hurricane

A red checklist on a grey circle backgroundWhen it comes to preparing for a hurricane, the first thing you should do is gather information.

There are a few ways to do this. First, know if you live in an evacuation area. Then assess your risks and know your home and business’ vulnerability to storm surge, flooding, and wind. Then pay attention to National Weather Service watches and warnings.

You should also keep a list of contact information for reference. The National Hurricane Center recommends knowing the following numbers:

Emergency Management Offices

County Law Enforcement

County Public Safety Fire/Rescue

State, County, and City/Town Government

Hospitals

Utilities

American Red Cross

TV Stations

Radio Stations

Your Property Insurance Agent

Your Commercial Weather Service Provider/Meteorologist (If you have one at your business)

Then you should perform a risk analysis. Check your hazards with FEMA’s Map Portal and rate your flood risk with the government’s flood portal.

If you live in an area that experiences hurricanes it’s a good idea to make sure you have a hurricane supply list on hand. Our meteorologists recommend including the following on your hurricane supply checklist:

A red check mark with a transparent background Water – plenty of water for you and your family

A red check mark with a transparent background Food – Nonperishable food

A red check mark with a transparent background Flashlight

A red check mark with a transparent background Batteries

A red check mark with a transparent background Keys

A red check mark with a transparent background Cash

A red check mark with a transparent background Blankets/Pillows

A red check mark with a transparent background Clothing

A red check mark with a transparent background First aid supplies

A red check mark with a transparent background Medications

A red check mark with a transparent background Documents – Social security cards, insurance information

A red check mark with a transparent background Can opener/Tools

A red check mark with a transparent background Dust masks

A red check mark with a transparent background Crank radio

A red check mark with a transparent background Charged phone

A red check mark with a transparent background Special items for babies, the elderly, and pets

Hurricane Tracking

Part of being prepared for a hurricane is understanding when one is coming, what its strength is, and what conditions are associated with it. The latest weather reports from trusted sources like the National Hurricane Center (NOAA, NWS) and meteorologists like the ones here at Earth Networks are the best ways to track a hurricane.

A lot of people wonder if there are any warning systems for hurricanes. The National Weather Service has hurricane watches and warnings to help everyone stay prepared.

Professional-grade weather maps are another great source of real-time hurricane tracking as well as hurricane watches and warnings.

Hurricane Watch

A hurricane watch is an indication that hurricane conditions (sustained winds of 74 mph or greater) are possible within your area within 48 hours.

If a hurricane watch is active for your area, you should quickly start preparing. This is because it is often too dangerous to prepare for a hurricane once winds reach tropical storm force. 48 hours should be plenty for you to secure your property, retrieve supplies, and/or evacuate.

Folks under hurricane watches should pay attention to the National Hurricane Center’s updates and heed official warnings and evacuation orders.

Hurricane Warning

After hurricane watches, hurricane warnings are likely. When hurricane impact seems more likely the National Weather Service issues hurricane warnings.

Hurricane warnings are issued 36 hours in advance and indicated that hurricane conditions (sustained winds of 74 mph or greater) are expected.

During a hurricane warning, you should complete storm preparations and immediately leave the threatened area if directed by local officials.

Tropical Storm Watch

It’s important to note that there are also tropical storm watches and warnings. A tropical storm watch is an announcement that tropical storm conditions (sustained winds of 39 to 73 mph) are possible somewhere within the specified coastal area within 48 hours.

If a tropical storm watch is active for your area, you should keep an eye on the forecast. This will help you stay updated with the intensity and direction of the storm as it moves closer to your area.

Tropical Storm Warning

A tropical storm warning indicates that tropical storm conditions are expected somewhere within the specified coastal area within 36 hours.

Warnings are more definite than watches as the storm closes in on your area.

Mandatory evacuations will often occur during the warning stage if they haven’t started already.

Other Types of Watches and Warnings

Red flag icon with a grey circle backgroundStorm Surge Watch: There is a possibility of life-threatening inundation from rising water moving inland from the shoreline somewhere within the specified area, generally within 48 hours

Tropical Cyclone Public Advisory: Contains a list of all current coastal watches and warnings associated with an ongoing or potential tropical cyclone, a post-tropical cyclone, or a sub-tropical cyclone. This will also include the cyclone position, maximum sustained winds, current motion, and a description of the hazards associated

Tropical Cyclone Track Forecast Cone: This graphic shows areas under tropical storm and hurricane watches and warnings. It also shows the position of the center of the storm and its predicted track.

Cone of Uncertainty: This graphic shows where forecasters believe the center of the storm will remain with 60-70% certainty.

Hurricane Local Statement: Local NWS offices in areas affected by a tropical cyclone issue Hurricane Local Statements to keep the public, local decision makers, and the media current on potential storm impacts in their area.

The Hurricane Local Statement contains a succinct overview of the event and a generalized summary of potential impacts and preparedness information. Potential impact information is ordered based upon the greatest expected impact from the tropical cyclone within the NWS local office’s area of responsibility.

Tropical Cyclone Threats and Impact Graphics: These graphics provide a threat assessment in terms of potential hazard impacts within an NWS local office’s area of responsibility. The assessment scheme takes into account the forecast magnitude of the hazard, along with the associated uncertainty of the forecast.

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What to do During a Hurricane

Once you’ve prepared, all that’s left to do is to act.

A lot of people wonder how to stay safe from a hurricane. While paying attention to an accurate source of weather information is important, make sure you following this hurricane safety checklist:

A dark blue "1" in a red circle Listen to local authorities

A dark blue "2" in a red circle Pay attention to watches and warnings for your area

Follow evacuation orders the moment you get them

A dark blue "4" in a red circle Use flashlights, not candles

a dark blue "5" in a red circle Do not tape windows with a “X”

a dark blue "6" in a red circle Do not return/venture out until you’re told it is safe to do so

a dark blue "7" in a red circle Use a generator responsibly – Don’t run it inside or in a garage, even if the windows are open

What Happens After a Hurricane?

A red broom on a grey circle backgroundOnce a hurricane leaves your area you’re safe, right?

If only it was that simple. Areas that experience hurricanes can sometimes look like a war zone afterwards. The first thing you should do after a hurricane is make sure it’s really over. Some people mistake the calm eye of a storm to be the end of the hurricane. This is not the case. The only way to make sure is to hear it from local authorities, see it on radar, or consult with a meteorologist.

Once local authorities deem it safe for you to leave your home or building, clean-up begins. Make sure to take proper health precautions while cleaning up the mess left behind by a hurricane.

Hurricane Health Risks

A red heartbeat line that becomes the shape of a family: a child, a father, a mother, and another child, before turning back into a heartbeat graph over a grey circle backgroundBesides the obvious health risks associated with hurricanes and their violent conditions, there are more hurricane health risks when the storm moves out of the area.

One of the top risks is contaminated water. When extreme flooding impacts an area, sewage systems fail. That allows contaminated  floodwater to mix with rainwater. According to the AIR Worldwide Corporation, Vibrio pathogens sickened two dozens people and killed six after Hurricane Katrina. In Haiti, over 100 people died from E. coli contamination following Hurricane Matthew.

Another hurricane health risk after the weather improves airborne pathogens. From inhaling carbon monoxide from a portable generator running indoors to breathing in mold spores in flooded structures, dangers are everywhere.

Mosquitoes are another hurricane health risk. Pools of standing water left behind by hurricanes are the perfect breeding ground for these pests. Mosquitoes can carry disease, so it’s important to empty standing water from places like tires and buckets.

When people with chronic conditions experience a hurricane, they have a lower chance of surviving. Those who depend on dialysis, oxygen, and insulin cannot receive those life-saving services during a power outage or when hospitals are unsafe due to flooding or other damage.

Finally, the last hurricane health risk is trauma. Living through an experience like a hurricane can be extremely traumatic. After Harvey, social workers reported four times more patients than usual.

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Hurricane History

Hurricanes have always both interested and threatened humans.

A lot of people ask: “What was the worst hurricane in history?” While it‘s difficult to discern exactly what you mean by “worst” we‘ll make the assumption that you mean “dangerous.”

What are the 5 Deadliest Hurricanes in U.S. History?

A dark blue "1" in a red circle The Great Galveston Storm (1900)

The Great Galveston Storm is known as the deadliest storm in American History. This hurricane killed somewhere between 8,000 and 12,000 people. This quick-forming storm coupled with limited detection and forecasting technology at the time all but ruined the thriving city when it made landfall on September 8, 1900.

A dark blue "2" in a red circle Hurricane Maria (2017)

The second deadliest storm in American history was Hurricane Maria. Nearly 5,000 people died when this storm slammed into Puerto Rico as a Category 5 hurricane. It then hit the U.S. mainland.

The Okeechobee Hurricane (1928)

This hurricane first devastated Puerto Rico before slamming Palm Springs, Florida, and flooding Lake Okeechobee. More than 18 inches of rain fell in a day. The Okeechobee Hurricane killed as many as 3,000 people.

A dark blue "4" in a red circle Hurricane Katrina (2005)

The next hurricane on this list is another one that most people will remember. Hurricane Katrina claimed the lives of 1,833 people when it hit Louisiana, Mississippi, Florida, and Alabama thanks for historic flooding that topped levees. FEMA did not arrive until 5 days after the storm which garnered sharp criticism.

The Cheniere Camindad Hurricane (1893)

We have to go back over 100 years ago for the last entry on our list. The Cheniere Camindad Hurricane killed somewhere between 1,100 and 1,400 people. Also known as the Great October Storm, this hurricane wiped out an entire Louisiana fishing community.

A red question mark over a grey circle background

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Hurricane Resources

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