Be ready for another season of above-normal hurricane activity in the Atlantic.

That’s the warning from the National Oceanic and Atmospheric Administration, which is predicting anywhere between 13 and 20 named storms in 2021, including three to five major hurricanes.

There is no telling yet how many storms will make landfall, but experts caution that a storm does not need to be a major hurricane to cause damage, and extreme flooding and winds can occur hundreds of miles inland, not just on the coastline.

“People tend to focus on the category of the storm but storm categories are completely based on wind speed,” said Keith Acree of the North Carolina Department of Public Safety. “What does most of the damage is not the wind, it’s the water.”

When a hurricane is poised to make landfall and the authorities issue an evacuation order, you may not have much time before you leave to protect your home and your family from the storm — and from flooding.

So here’s what you can do to get ready ahead of time.

Before the Storm

Make a family plan.

Prepare an emergency kit, including cash, prescription medicines and three days’ worth of food and water (for people and pets). If your house floods and you can’t return immediately, this is essential. Be sure to consider provisions for those with special needs, like older people. If you need help coming up with a list, this one from Wirecutter, a New York Times company, has suggestions for any household.

If you live in a coastal area, it’s important to become familiar with community evacuation plans, evacuation zones and evacuation routes.

And plan a meeting spot for your family. Deanna Frazier, a spokeswoman for the Federal Emergency Management Agency, said that forgetting to do so was one of the most common mistakes when Hurricane Harvey landed as a Category 4 hurricane in Texas in 2017. “Cellphones may not work or you may not have your cellphone with you,” she said. “There were a lot of people who were looking for loved ones and disconnected from them. Those are the kinds of things that you need to think about.”

Listen to local news media for the most up-to-date information on how to prepare and when to evacuate the area. “The biggest issue I see people running into is that they just wait too long,” said Alberto Moscoso, a former communications director for the Florida Division of Emergency Management. “When it comes to hurricane and storm preparation, now is always the right time.”

Protect your documents and valuables.

Photograph or scan important documents like driver’s licenses, social security cards, passports, prescriptions, tax statements and other legal papers. Upload the images online for safekeeping. Store documents in a fireproof, watertight container, or take them with you. FEMA’s Emergency Financial First Aid Kit has a checklist of documents you’re likely to need to claim insurance and other benefits.

When the time comes to evacuate, take irreplaceable keepsakes with you, if possible. Otherwise, move belongings with sentimental or monetary value upstairs or to high shelves to protect them from floodwaters. It’s common for people to underestimate how high the water will go.

“Anywhere it rains, it can flood,” Mr. Acree said.

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If possible, make sure that your home has flood insurance. Most homeowner’s policies do not cover flood damage, and flood insurance takes 30 days to become effective.

As the storm approaches

Bottle water and freeze food.

The Food and Drug Administration recommends switching your refrigerator and freezer to the coldest possible settings and moving fridge items to the freezer so they stay cold longer if the power goes out. Even in a power failure, a tightly packed freezer can stay cold for 48 hours. If you can’t fit everything into the freezer, add containers of ice to the fridge.

Keep thermometers in the fridge and freezer so you can check the temperature when you return. Anything that has remained at 40 degrees Fahrenheit or colder is safe to eat. Move pantry items and a supply of bottled water to high, secure shelves so they will be safe from floodwaters.

Take stock of household chemicals.

Look for any potentially dangerous substances, like bleach, ammonia and drain cleaners. Check in the garage. Make sure all lids are tightly closed and move these items to high shelves, as far from potential flooding as possible. Chemicals that mix into floodwaters can be hazardous to your health or cause fires and explosions.

Think about power.

Move electronics, small appliances, portable heating systems and other things with wires to upper levels and high shelves — as far away from water as possible. If you have a generator, keep it away from moisture. (Never use it inside or plug it into a wall outlet.)

Clear the yard and secure windows.

Trim and safely dispose of tree branches, which can fall during hurricane winds or become projectiles if left on the ground. Secure rain gutters and downspouts, and clear clogged areas that could stop water from draining from your property. Move bikes, trash cans, outdoor furniture, grills, tanks and building materials to a secure spot, either inside or tied down, as these can fly in high winds. Board up your windows to prevent leaks and broken glass, and, where necessary, secure doors with storm shutters.

After the Storm

Stay safe.

Avoid driving or walking through floodwaters, which can be electrically charged from downed and underground power lines; contain debris like glass, dead animals or even poisonous snakes; or be contaminated with sewage and hazardous chemicals. Just six inches of moving water can knock down a person, and a foot of fast-moving water can destabilize a vehicle.

Don’t enter your house until officials say it is safe to do so. To avoid electrical hazards from flooding, turn off the electricity at the main fuse box or circuit breaker, or ask for professional help. Go inside with caution — don’t touch electrical equipment, and use a flashlight, rather than anything flammable, in order to see.

When in doubt, throw it out.

Only bottled water, canned and well-packaged foods are safe to consume after a flood. The Centers for Disease Control and Prevention advises throwing away any food that may have come in contact with water. If cans get wet, remove their labels and wash them in bleach solution to be safe.

Waterborne diseases are also a risk — only drink fresh, bottled water. If this is not accessible, boil water according to C.D.C. guidelines.

Clean up properly.

Hazardous chemicals, mold, asbestos and lead paint are all potential dangers in the aftermath of a flood — so follow official recommendations and wear gloves, eye protection and face masks on any flood-damaged property. Before beginning cleanup and debris removal, take photographs of your home and contact your insurance company, then air out and remove all water-damaged items. This is the most important step toward minimizing mold, which can cause asthma attacks, eye and skin irritation and allergic reactions.

Adeel Hassan contributed reporting.