Flooding is the overflowing of water onto dry land. Floods can happen as a result of heavy rains, ocean storms, rising sea levels, snow melt, or breaks in dams or levees. Of all the weather-related natural disasters that occur, floods are the most common. Even a few inches of water can cause significant damage to property, but many flooding events involve deep, fast-moving water. Flash floods can last just minutes, while other types of flooding can persist for weeks. As a result of the effects of climate change, flooding is increasing in frequency and severity across the United States.
There are many different causes of flooding. Here is a look at some of the most common.
Floods are the most common disaster in the United States and therefore have a powerful economic and personal impact. The consequences of flooding can vary widely depending on the type, location, duration, depth and speed. It is also important to consider the vulnerability, value, and population of the affected area. In natural systems, floods serve the beneficial purpose of maintaining key ecosystem functions and biodiversity. All but the most extreme floods serve the natural purpose of altering river beds, rejuvenating wetland habitats, and triggering breeding events, migration, and dispersal. Yet, when floods encounter human infrastructure they can cause direct and harmful impacts.
Every year in America, floods cause massive damage to homes and infrastructure. In 2019, floods were responsible for over $3.75 billion worth of property and crop damage in the United States. This destruction can stem from the strong force of the water, the impact of debris carried within the water, or lingering effects of water exposure. Possessions within flooded houses can be submerged and carried away and water can lead to structural problems and mold growth.
The immediate damage of a flood to the property, land, and infrastructure of a city can be disastrous. But the damage done by ongoing flood conditions can cause a variety of equally challenging secondary effects. Flood conditions can cause waterborne illnesses, disruption in communication services, economic standstill, and dislocation of people. In the long term, these effects can leave communities deeply impacted and economically vulnerable for years to come.
The severity of local damage varies widely by location. Many population centers are at very low risk of experiencing floods because they are not within immediate proximity of large bodies of water or subject to extreme rainfall. However, most areas of the U.S., even dry and mountainous regions, are susceptible to some type of flooding. Other towns are more prone to the risks of flooding and therefore more likely to be subject to both mild and extreme effects of flooding. Individual home damage resulting from flooding can also vary widely. The amount of damage depends on the vulnerability of the property and the proximity of the home to the most heavily impacted areas.
Climate change is creating conditions that are worsening the frequency and severity of flooding. Storms are getting more severe on average as global temperatures rise, causing more frequent flooding. Storms are also creating more moisture than previously which increases flood risk. In fact, storms now generate 27 percent more moisture than they did 100 years ago.
Apart from dramatic storms, rising global temperatures are leading to more evaporation from rivers and oceans and changes in streamflow and snowmelt conditions. Each of these changes can cause river flooding to dramatically decrease in some locations and increase in others. Instability and uncertainty of flood patterns and risk due to climate change is likely to be an increasingly significant issue.
People who live in recognized flood zones are at the most risk of having their properties damaged by floods. Flood zones are geographic areas which have been designated by FEMA for having a high risk of floods. Most flood zones are land that is near bodies of water such as rivers, lakes, ponds, streams, or oceans, or in areas that get a large amount of rainfall each year.
To help understand rapidly changing flood risks, FEMA publishes flood maps that can give information about local flood risks.
In addition to flood zones, your home can have a higher risk of being damaged by a flood if it is in one of the states most vulnerable to flooding.
4. New York
5. New Jersey
Cities with high flood risk include:
Anyone who is considering buying a home should carefully weigh the risks of investing in a flood-prone area. The ClimateCheck property report and FEMA flood maps are powerful tools to help assess specific flood risk for properties you are considering purchasing. For those already invested, here are a variety of adaptation options:
Purchase appropriate flood insurance.
Upgrade your home to increase resistance to flood events.
Floods are widespread, frequent, and can be highly destructive. Due to climate change, it is likely that they will only get more severe over time. Cities and towns that are on the coast and that are close to sea level are at especially severe risk for floods. If you are concerned about your property being damaged by floods, then you should take what steps you can to mitigate risks. Your best protection, however, is to avoid purchasing in a flood-prone area.
If you currently own a property or are looking at purchasing, you can assess your risks with the ClimateCheck property report.