The 2021 Atlantic hurricane season will likely end with 21 named storms, the third most in recorded history.   Of these storms, a little less than half were tropical storms, not hurricanes. While this may seem like an important distinction, the only thing separating these two storm categories is 1 mph of sustained wind speeds.
A tropical storm is a tropical cyclone with maximum sustained wind speeds of 39 mph to 73 mph
A hurricane is a tropical cyclone with maximum sustained wind speeds of 74 mph or higher
Hurricanes also have the potential to be more destructive than tropical storms — wind speeds for a Category 4 are roughly double that of a tropical storm. For this reason, homeowners insurance policies in high-risk coastal areas often include separate deductibles that apply to hurricane-related wind damage claims.
A hurricane’s life cycle is made up of four stages: tropical disturbance, tropical depression, tropical storm, and hurricane
It’s possible for a hurricane to weaken to a tropical storm or depression and restrengthen to a hurricane during its life cycle
Homeowners insurance companies often have rules and restrictions around how tropical storm and hurricane damage are covered
A tropical cyclone goes through multiple phases of development before officially becoming a hurricane. Here’s a breakdown of the four stages in a hurricane’s life cycle.
A tropical disturbance usually forms in tropical waters near the equator. Once water warms to around 80 degrees Fahrenheit, it turns into moist air and rises, eventually condensing and forming columns of clouds.
This cloud formation generally leads to rain and additional thunderstorm clouds as the storm system moves through the water. At this point, the system isn’t generating high wind speeds, but it is forming the foundation of the hurricane.
As the clouds continue to rise and get larger, a cooler, higher pressure area starts to form at the top of the cloud columns. Wind is pushed outward away from the high-pressure area, creating areas of low pressure near the surface of the water.
Air is then funneled toward the lowest pressure area (the “eye” of the storm), which rises and forms circulating winds and thunderstorms. The storm is officially a tropical depression once wind speeds reach 25 to 38 mph.
A tropical depression is upgraded to a tropical storm once sustained wind speeds reach at least 39 mph. This is also when the storm is officially named. By this point, the storm is starting to closely resemble a hurricane.
Once the cyclone reaches sustained wind speeds of at least 74 mph, it’s officially upgraded to a hurricane.
Hurricanes are typically 50,000 feet high and 125 miles across, with an eye of around 5 to 30 miles wide, according to the National Oceanic and Atmospheric Administration (NOAA). 
Water typically accumulates at the eye of the storm, which can lead to catastrophic storm surge and flooding once the hurricane makes landfall. In fact, storm surge — not wind — is the most dangerous component of a hurricane, according to the NOAA. 
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Hurricanes are given a 1 to 5 rating based on their maximum sustained wind speed according to the Saffir-Simpson Hurricane Wind Scale.
A standard homeowners insurance policy covers damage caused by wind, including when a tropical storm or hurricane is the source of the damage. But in many hurricane-prone states, insurance companies will only cover tropical storm or hurricane damage if certain conditions are met. This usually means you’ll have a separate named storm or hurricane deductible for damage caused by named storms.
A named storm or hurricane deductible is separate from your standard homeowners insurance deductible. It’s only triggered for damage to your home or belongings caused by a hurricane or named storm.
These deductibles are generally higher than the standard policy deductible applied for fire, theft, and other types of covered damages. This allows insurers to provide coverage in high-risk areas and keep home insurance rates down. Without the separate deductible options, insurance companies likely wouldn’t be able to take on the high risk.
The history of hurricane deductibles
Nineteen states and Washington, D.C. have some type of hurricane or named storm deductible in place. Insurance companies began implementing these deductibles in 1992 after Hurricane Andrew caused around $16 billion in insured losses. They became even more common after Hurricane Katrina in 2005, a storm that caused $65 billion in insured losses.
Your policy deductible is the amount you’re responsible for paying before your insurance will kick in to cover a claim. Most policies apply a single dollar amount deductible, like $500 or $1,000, for every type of loss covered by your policy.
But in many hurricane-prone states, insurance companies apply a separate, higher deductible for wind damage caused by a hurricane or named storm. In some states like Texas, this deductible may apply to any type of wind damage, regardless of the storm type.
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Named storm deductibles are generally listed as a percentage of 1% to 10% of your home’s insurance amount rather than a set dollar amount.
Let’s take a look at an example.
If your home is insured for $300,000 and you have a 3% hurricane deductible, you have to pay $9,000 out of pocket before your insurance will cover the remainder of a hurricane damage claim.
Similar to your regular deductible, you choose your percentage deductible when setting up your policy. A higher percentage deductible means lower rates, but make sure it’s set at an amount you can afford if you need to file a claim.
In some states, insurance companies may trigger separate percentage deductibles depending on whether the damage was caused by a tropical storm or a hurricane.
Named storm deductible: Applies to named tropical storms that reach maximum sustained wind speeds of 39 mph
Hurricane deductible: Applies to named storms that reach maximum sustained wind speeds of 74 mph.
These deductibles are often triggered once the National Weather Service or National Hurricane Center officially declares a named storm or hurricane warning.