What Is a Coastal Flood Advisory? 

A coastal flood advisory, also known as sunny day flooding, is the lowest level of flood warning — but it can still cause challenges for your vehicle and home if you’re not prepared. 

Here we share what a coastal flood advisory is, how it happens and the steps you can take to protect your home, vehicle and belongings. 

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What is a coastal flood advisory? 

A coastal flood advisory is an advisory issued by the National Weather Service to alert those in the local area that a tidal flood is imminent or has already occurred. 

Coastal flood advisories are also known as coastal flood warnings, tidal flooding, sunny day flooding and even nuisance flooding. A coastal flood advisory is the lowest level of flood warning that can be issued. 

What is a coastal flood warning, and what does it mean? 

Receiving a coastal flood advisory warning means low-level tidal flooding is about to occur, or has already occurred, in the following areas: 

• Parking lots located near the shoreline. 
• Low-lying coastal roads.
• Basements or yards of homes in coastal neighborhoods.

Coastal floods occur when ocean and weather conditions combine to push water levels above their usual levels, and can be influenced by the following factors: 

• Time (coastal flood advisories typically occur during high tide).
• Storm surge.
• Wave action.
• Full moon cycles.

Because this type of flooding is tidal, it can, and frequently does, occur without rain.

The impact of a coastal flood advisory

Compared to other types of more severe flooding, damage caused by sunny day flooding tends to be minimal. However, even just a few inches of flooding can bring challenges like road closures, travel delays, vehicle damage and saltwater intrusion into drainage systems and vehicles. 

Sunny day flooding usually lasts only a few hours and occurs about four to eight days per year on average in the U.S. By the year 2050, it’s expected to increase to 45 to 70 days per year. 

How to prepare for a coastal flood advisory

One of the biggest mistakes you can make with a coastal flood advisory is to underestimate the potential for damage and not take precautions. 

Fortunately, there are several simple steps you can take to protect your valuables and minimize damage or the cost of vehicle or home repair.

Insurance Type	Action Step	Why It Matters
Auto	Move your car to higher ground.	Sunny day flooding hits low-lying lots first — a short move keeps your car dry.
Auto	Rinse the undercarriage after exposure.	Salt water speeds up rust and corrosion, so a quick rinse protects your investment.
Auto	Avoid driving through flooded roads.	Just a few inches of water can damage your engine or cause you to lose control.
Auto	Review your comprehensive auto coverage.	Basic liability won’t cover flood damage — comprehensive coverage typically does.
Homeowners	Secure outdoor furniture and bring valuables inside.	Loose items can become damaged or swept away in rising water.
Homeowners	Clear debris from drains.	Clear drains let floodwater escape efficiently instead of pooling near your home.
Homeowners	Seal basement openings and add sandbags.	Small cracks let water in fast — caulk and sandbags add an extra layer of defense.
Homeowners	Move valuables off the floor.	Many flood policies require reasonable protective steps — this is an easy one.
Homeowners	Consider a flood insurance policy.	Standard homeowners insurance usually excludes flood damage — a separate policy fills the gap.

How to protect your vehicle from sunny day flooding

• Move your vehicle to higher ground: Sunny day flooding occurs on lower-level ground. Protect your vehicle by avoiding coastal parking lots and parking in a more elevated area. 
• Rinse your car’s undercarriage: Salt water can speed up rust and corrosion. Rinse your car’s undercarriage, or any other part of your vehicle that was in contact with the salt water to minimize the effects of salt exposure. Consider coating your vehicle’s underside with a preventive rust treatment before the flooding sets in. 
• Stay away from flooded roads: Avoid driving through floodwater. Even just a few inches of water can do damage to your vehicle or cause you to lose control, so adapt your journey accordingly.
• Consider comprehensive auto insurance: Basic liability insurance won’t protect your car from flood damage. Instead, most comprehensive auto insurance usually protects against floodwater damage, including engine, electrical, upholstery and more. 

Bear in mind that comprehensive coverage may not protect personal items stored in the vehicle. Coverage also typically excludes electric vehicles, which come with additional flood risks, like an overheating battery. 

If your vehicle has been damaged thanks to sunny-day flooding, document the damage and notify your insurer. 

How to protect your home from sunny day flooding

• Secure outdoor furniture: Ensure any outdoor furniture is tied down and bring valuables inside. 
• Clear drains: Remove debris from any drains to help floodwaters drain efficiently. Dispose of any nearby trash to prevent clogging your drainage system. 
• Seal basement openings: Caulk can be used to seal cracks or other small openings in your basement. Consider lining the lower-level parts of your home with sandbags as an extra layer of security. 
• Remove valuables from the floor: Move valuables onto a surface or a higher level of the house. Some flood insurance policies require you to take reasonable steps to protect your valuables. 
• Consider flood insurance: Flood insurance must be purchased separately from your homeowners insurance. Even if your home isn’t located in a high-risk area where flood insurance is required, purchasing it can be a smart move. 

Most home insurance policies won’t cover damage caused by flooding, but a flood policy typically protects your home’s structure, carpeting, damaged cabinets, electrical and plumbing systems, personal property and more. 

Learn more about what to do if your house floods.

Coastal flood advisory FAQs

What is sunny day flooding? 

Sunny day flooding refers to temporary flooding that occurs in low-level, coastal areas when sea levels temporarily rise. It’s also known as coastal flooding, nuisance flooding or tidal flooding.

Which U.S. state has the highest risk of coastal flooding? 

In the U.S., Florida, New York, New Jersey, Louisiana and Massachusetts have the highest risk of coastal flooding, according to Climate Central.

How long does a coastal flood advisory typically last?

Most coastal flood advisories last just a few hours, tied to the timing of high tide. Once the tide recedes, water levels typically return to normal.

What’s the difference between a coastal flood advisory and a coastal flood warning?

A coastal flood advisory signals minor, nuisance-level flooding — think a few inches of water in low-lying areas. A coastal flood warning indicates a more serious threat, with higher water levels that can cause significant property damage or pose a safety risk.

Does homeowners insurance cover sunny day flooding?

Typically, no. Standard homeowners insurance excludes flood damage, including tidal or nuisance flooding. Protecting your home’s structure and belongings from this type of flood usually requires a separate flood insurance policy.

Is it safe to drive during a coastal flood advisory?

Driving through flooded roads is never a safe bet, even during a minor advisory. Just a few inches of water can stall your engine, damage electrical components, or cause you to lose control of your vehicle. Reroute around flooded areas whenever possible.

How much advance notice does the National Weather Service give for a coastal flood advisory?

The National Weather Service usually issues coastal flood advisories a few hours to a day before expected tidal flooding, often tied to predictable high-tide cycles and lunar phases. Checking local forecasts during full moon periods can help you stay ahead of it.

Can sunny day flooding cause long-term damage to a home’s foundation?

Repeated exposure to sunny day flooding can gradually weaken a foundation, especially if water seeps into cracks or basement openings over time. Sealing entry points and addressing drainage issues early helps minimize this risk.

Coastal flood advisories can be a nuisance, but as the climate changes, they’re becoming a reality for more and more people. Fortunately, with the right precautions and insurance protection, you’ll be able to protect your vehicle, home, and valuables. 

Sunny day flooding won’t wait for a forecast — make sure your car and home are covered before it strikes. Get a fast, free AAA auto, home or flood insurance quote today and protect what matters most.

Last updated on August 4, 2026 by AAA Staff