Flooding is arguably the most destructive type of disaster in the US. It hurts more people and destroys more property every year than high winds, tornadoes, or lightning.
As an example of the devastation floods can cause, just compare Hurricane Andrew to Katrina. Andrew hit the US coast with winds in excess of 170 miles per hour, stripping buildings from their foundations. In New Orleans, winds from Katrina were clocked at 100 miles per hour—still dangerous, but milder by comparison.
Yet the overall cost of life and property from Hurricane Andrew was just a fraction of Katrina’s.
Katrina unleashed literal rivers of water onto gulf coast states in a matter of hours that crept into every piece of infrastructure and stuck around much longer than wind gusts.
Signs You May Live in a Flood Zone
But it’s not just hurricanes. Ninety percent of natural disasters involve flooding— spring thaws, tropical storms, heavy rains, flash floods, levee and dam breaks, and more. It’s our nation’s most frequent and costly natural disaster.
Here are signs that you may live in a flood zone.
YOU LIVE ON THE COAST
Let’s cover the obvious one first. Coastal areas have always been at risk of flooding and it’s only getting worse. Rising sea levels, increases in rainfall, and ongoing erosion are combining to create a swell in flooding events.
One of the deadliest types of floods that' become more frequent and severe is the surge that hits the coast during major storms. Water from storm surge can rise 20 feet or more, battering buildings, roads, and other infrastructure.
YOU’RE IN A DENSELY POPULATED AREAS
The concrete, asphalt, etc. in urban and suburban areas absorb less water, leading to more frequent flooding.
You don’t need to live in “hurricane alley” to be right at the center of a flood bullseye. If you live in a densely populated region—from downtown urban centers to the suburbs (that’s about 83% of us)—there’s a good chance your area is at risk of floods.
The reason is simple: concrete and asphalt in urban and suburban areas reduce the amount of rainfall absorbed into the earth. This greases the skids for flash floods during major storms. Storm drains also frequently overload and run out onto the street.
YOU LIVE NEAR A SMALL STREAM
Of course, if you live near a large river, you’re vulnerable to flooding. Massive storm fronts can fill the basins and streams that feed into large rivers, causing them to seep.
What you may not know is that streams can actually be just as susceptible (or more) to flooding. The reason? Because run through smaller channels, streams are more easily inundated by shorter rainstorms in a more localized area.
Saturated land can raise the level of groundwater and lead to flooding that takes a very long time to recede.
YOU LIVE IN AN AREA WITH HIGH GROUNDWATER TABLES
We’ve all seen the images of waves cresting into cities and rivers bursting their banks. But slow, seeping groundwater flooding can be every bit as destructive, especially since it takes so much longer to recede. Groundwater flooding is most common in low elevation areas with an underlying, permeable foundation like sandstone or chalk.
THE LAND AROUND YOU IS SINKING
It’s not just rain and groundwater: human activity can contribute to flood risks, too. If you live in an area where groundwater has been depleted, the land around you could be experiencing “subsidence,” where the earth sinks because aquifers beneath it are emptied. This creates problems with drainage and wider expansions of flood water. It can also produce tidal inundations that make floods in coastal areas even worse.
YOU LIVE NEAR ONE OR MORE LEVEES
This is a big one. Rivers, especially ones with levees, are vulnerable to flooding. There are nearly 100,000 miles of levees across the US, and like so much of our infrastructure, they’re outdated and falling apart.
Some have eroded. Others, like the storm walls that broke during Katrina, are lower than they need to be because of sinking land. Some are built on flawed or outdated elevation data. Others have deteriorating channel and gate systems that will fail unless they’re updated.
You may be in striking distance of a levee and not know it. Millions of Americans live near at least one—of those, 45% of are near a “high-risk” levee. Check out the National Levee Database and see your proximity. You might be surprised at what you find.
YOU LIVE DOWNSTREAM OF A DAM
Like levees, many dams in this country are falling apart. Recent data from the federal government’s National Inventory of Dams reveal that 15,000 of the dams in the US would likely cause fatalities if they broke. Even worse, 2,300 of them are in “poor” or “unsatisfactory” condition.
Fortunately, dam failures are uncommon. Unfortunately, the state governments that manage many dams don’t have the resources they need to repair and upkeep them. “[Repairs] can be very expensive,” said Mark Ogden, co-author of an American Society of Civil Engineer’s 2017 study that gave US dams a “D” grade. “It takes a lot of time and resources to go through the [repair] enforcement process.”
For a list of the states most threatened by high-hazard, deficient dams, click here.
YOU LIVE NEAR RUNOFF
In the American West, runoff flooding from snowpack is common. You don’t have to see snow out your window to be in a runoff area, either. Over half of the runoff out west comes from snow and ice, and whenever it exceeds the capacity of catchment systems, flooding can occur.
How to Prepare
Flooding can be devastating. Luckily, there are things you can do to prepare.
Protect Your Home
Building a drainage system around the perimeter of your property can help protect against certain types of flooding.
- Elevate – Even if you’re in a flood zone, living at a higher elevation seriously mitigates your risk.
- Waterproof your basement – This can include something as simple as a French drain, or more expensive options like water membranes or complete remodels. Make sure to place a sump pump strategically in your basement with separate backup power in case the electricity shuts off.
- Keep valuables out of harms way – Move valuable items that you don’t want to replace to higher ground—a second story if you have one, or at least out of the basement.
- Get insured – No matter how well you prepare, you cannot stop the hand of God. If you haven’t already, get flood insurance on your home. FEMA manages the National Insurance Program (NFIP), a network of about 60 insurance companies that can help get you good coverage at a reasonable rate.
- Make a plan that covers you for two weeks or more – Write a disaster plan specifically designed for floods. Know where you’re going to shelter for at least two weeks and how you plan on cleaning the damage.
Cars are strong machines, but water is a force of nature. Never attempt to pass through a flooded crossing...you're liable to get stuck, submerged, or even swept off.
- Listen to authorities – Listen for warnings and advice from trusted authorities at places like the National Weather Service, NOAA, and elsewhere. If you live near a dam or levee, the organizations that manage them should have contingency plans in case they fail. Locate your levee or dam authority and get to know your regional plan.
- Avoid danger areas – Danger areas include low spots like underground parking garages, basements, and low water crossings. Even if drowning isn’t an outcome, the water could be contaminated and make you ill.
- Know the signs – Other than water visibly entering your area of the home, other signs of flooding can include things like marshy ground and damp walls.
- Be ready to move – Flooding can happen very quickly. Make sure you have emergency plans in place for shelter, evacuation, and communication. This will make it much easier to move act decisively and move quickly.