A house in Texas is surrounded by floodwaters. Berrier hit the state as a Category 1 hurricane. The storm’s remnants are expected to move from the ocean toward the Midwest, where they will also bring dangerous flooding risks.
Brandon Bell/Getty Images/Getty Images North America
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Brandon Bell/Getty Images/Getty Images North America
Beryl made landfall as a hurricane in Texas, and it was predicted that as the storm developed it would penetrate deep into Midwestern states such as Missouri, Illinois, Indiana, Michigan, and even Ontario, Canada.
Most people don’t associate flooding far from the coast with hurricanes. But even if these storms lose hurricane status, separate and move away from the ocean, they can still cause severe flooding. Climate change is making these storms more dangerous. A hotter atmosphere holds more moisture, making rainfall more intense.
Why on earth does a hotter planet mean greater risk of inland flooding? What does the future hold? This FAQ is for the millions of people living in flood-prone areas of the United States who want to know how to stay safe and prepare for climate change.
How does climate change affect heavy rainfall?
It all starts with the release of greenhouse gases like carbon dioxide and methane. As humans continue to burn fossil fuels, the atmosphere is getting hotter. Hot air holds more water vapor, so when it rains it rains harder.
For decades, climate scientists have predicted that heavy rains would become more common as the planet warms. At this point, scientists can instantly measure what’s happening. According to the National Climate Assessment, rainfall from the heaviest storms has increased across the country – with rainfall in the Northeast increasing by about 60% since the 1950s. Significant increases in rainfall are expected across the Northeast and Midwest, meaning there is an increased risk of flooding in a variety of places, including areas far from the coast.
Why are inland flooding so dangerous?
Because floods occur very quickly and the water flows with great force. When a lot of rain falls in a short period of time, it won’t seep into the ground, especially if the ground is already saturated or covered by impermeable sidewalks or buildings.
All this water has to go somewhere, so it collects on the surface. If there’s a hill – even a small one – water will start flowing down the hill. It gathers strength. This is what causes flash flooding and can be extremely dangerous. Moving water could tear homes from their foundations, damage roads, flood underground subway stations and sweep away cars. Here’s why floods remain one of America’s deadliest natural disasters
Are there warnings before flash floods occur?
There are usually some caveats. The National Weather Service is keeping an eye out for signs of heavy rain. If flash flooding is possible, the local weather service office will issue a flash flood warning. If flooding is possible, the watch turns into a full flash flood alert.
People with smartphones often receive automatic alerts when there is a weather warning. It is important to take these warnings seriously and especially avoid areas that have been flooded in the past or are low-lying areas. Driving during a flash flood is especially dangerous. Never drive into moving water, even if it appears shallow.
What measures can be taken to protect people from heavy rain?
There are many, many ways to warn people of approaching floods, slow down water flow, and provide a safe place for water to go. For example, if there are fewer sidewalks, it helps water seep into the ground. Healthy forests and wetlands also absorb water. Detention ponds are also common, especially near areas with lots of sidewalks, such as highways and parking lots. Ponds are low-lying marshy areas that collect excess water.
One of the reasons why heavy rains cause massive flooding in cities is that underground pipes are not large enough to handle the heavy rain that is falling. Most stormwater systems in U.S. cities were built decades ago. Installing larger pipes or installing pipes in a new location is very expensive. But it’s an important piece of the puzzle, especially in densely populated urban areas where heavy rains are expected to become extremely common in the coming years.
Where to go in the future? Will the heavy rain continue to fall?
It depends on humans stopping emitting greenhouse gases. If humans continue to burn vast amounts of oil, gas and coal, the atmosphere will continue to get hotter and heavy rains will become more common and more severe this century.
If humans drastically reduce greenhouse gas emissions over the next decade or so, it will help control heavy rainfall, especially later in the century.
This is an updated version of a story originally published in 2022.
