This week's floods in Vermont, where torrential rains caused devastation even miles from any river, are testament to a particularly dangerous climate threat: Flood disasters are occurring more and more everywhere, with almost no warning.
And the United States, experts warn, is completely unprepared for the threat.
The idea that wherever it can rain, it can flood is not new. But rising temperatures exacerbate the problem: They allow the air to hold on to more moisture, causing more intense and sudden rainfall out of nowhere. And the implications of that shift are enormous.
“It's getting harder and harder to adapt to these changing conditions,” said Rachel Cleetus, policy director for the climate and energy program at the Union of Concerned Scientists. “It's just everywhere, all the time.”
The federal government has struggled to prepare American society for major flooding, by funding better storm sewers and pumps, building levees and sea walls and upgrading roads and other basic infrastructure. As seas rise and hurricanes get worse, the parts of the country most prone to flooding — places like New Orleans, Miami, Houston, Charleston, or even areas in New York City — could easily spend the entire government budget on climate resilience, without completing problem for one of them.
Federal flood maps, which the government uses as a guide for determining where to build housing and infrastructure, should be updated regularly. But they often fail to capture the full risk — a result of a lack of resources, but sometimes too rejection from local officials who don't want new boundaries in development.
And as Vermont's floods demonstrated, governments can't focus their resilience efforts on just plainly visible areas, near beaches or rivers.
But the country lacks a widecurrently, a national rainfall database that can help inform homeowners, communities, and governments about the increased risk of heavy rains.
In Vermont, the actual number of homes at risk of flooding is three times what federal flood maps show, according to data from the First Street Foundation, a New York-based nonprofit research group.
The so-called “hidden risks” are also very high in other parts of the country. In Utah, the number of properties at risk when considering rainfall is eight times that shown on federal flood maps, according to First Street. In Pennsylvania, the risk is five and a half times; in Montana, quadruple. Nationwide, about 16 million properties are at risk, compared with 7.5 million in the federal government's flood zones.
The result is severe flooding in seemingly unexpected places, like Vermont. Last summer, rainstorms closed parts of Yellowstone National Park, forcing visitors to evacuate. In March, torrential rains led to a federal declaration of disaster in six counties in Nevada, the country's driest state.
The Vermont floods highlight the need to spend more on flood event modeling and planning, said Mathew Sanders, who leads state resilience efforts for Pew Charitable Trusts. “You have to see how the water will flow,” he said. “We kind of need to re-imagine what the most strategic interventions are going to be.”
All that water often brings tragedy to the places it can least handle it.
Last year, torrential rains triggered flash floods that hit the eastern Kentucky basin. The force of the water tore several houses apart, crushed a truck, and clogged the remaining structures with mud and debris. More than 35 people died.
Communities scattered across the Appalachian Mountains are familiar with flooding, with water escaping from the creeks that flow through the area. But the ferocity of the flood made the old family confused. “We went from bedridden to homeless in less than two hours,” said Gary Moore, whose home outside of Fleming-Neon, Ky., was destroyed, days after the floods.
Floods exacerbated by climate change are also exacerbated by the long-lasting effects of coal mining, as the industries that once powered communities recede, leaving bare hillsides and mountains with their peaks blown off by the wind. The loss of trees worsens the speed and volume of rain runoff.
In Houston, deadly and catastrophic flooding has long been a familiar threat, so much so that the worst hurricanes have become a shorthand to mark time: Tropical Storm Beta (2020), Tropical Storm Imelda (2019), Hurricane Harvey (2017) and Tax Day Flood (2017). 2016).
But as many as half of the homes flooded in recent years are outside the official flood risk zone. An analysis by the Harris County Flood Control District found that 68 percent of homes that were inundated during Hurricane Harvey were outside the 100-year floodplain, due to surging water in the creeks and bays that flow through the area.
In Summerville, Ga., a city of about 4,400 people nestled on a ridge in the northwestern corner of the state, flash floods overwhelmed homes and businesses in 2021 following flooding caused by remnants of Tropical Storm Claudette. Most of Summerville fall outside the 100 year floodplainand the resulting destruction and cleansing flooded the city.
Flooding is also a source of frustration and pain in Horry County, SC, the coastal region that includes the resort town of Myrtle Beach. April O'Leary, a resident who started a group called Horry County Rising, said in a 2021 hearing with federal emergency management officials that nearly half of the flood-affected homes in the county were outside their designated flood zones.
“There's really no such thing as recovery when you flood,” said Ms. O'Leary to officials. “You never fully recover financially, and families continue to live in fear of flooding.”
As the threat of flooding and other climate shocks gets worse, the federal government has increased funding for climate resilience projects. The 2021 infrastructure bill provides an estimated $50 billion for such a project, the largest infusion in American history.
But the funds are still far below the requirement. This spring, the Federal Emergency Management Agency said it had received $5.6 billion in applications for its two main disaster preparedness programs – nearly twice as much as available.
Anna Weber, a senior policy analyst at the Natural Resources Defense Council who specializes in flood risk, said governments need to direct more money to the most economically vulnerable communities – the places that can least afford their own resilience projects.
But the scale of the intervention required is also an opportunity to right old wrongs, according to Amy Chester, managing director of Rebuild by Design, a New York-based nonprofit that helps communities prepare for and recover from disasters. He said cities could rethink how they build, returning to nature the land built on rivers, streams and wetlands, and creating new parks or other landscapes to hold down rainfall.
In that sense, he says, adapting to climate change is an opportunity. “When else?” asked Ms. Chester, “can you rethink how you want to live?”