This week’s flooding in Vermont, where torrential rains caused destruction for miles from any river, is evidence of a particularly dangerous climate threat: Catastrophic flooding can increasingly happen anywhere, when almost without warning.
And the United States, experts warn, is nowhere near ready for that threat.
The idea that wherever it rains, it can flood, is not new. But rising temperatures make the problem worse: They allow the air to hold more moisture, leading to more intense and sudden rains, seemingly out of nowhere. And the implications of that change 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 everywhere, all the time.”
The federal government is already struggling to prepare American communities for severe flooding, by funding better storm drains and pumps, building levees and sea walls and elevating roads and other basic infrastructure. As seas rise and hurricanes worsen, the parts of the country that experience the most flooding – places like New Orleans, Miami, Houston, Charleston or even parts of New York City – can easily consume the entire budget of government for climate stability, without solving the problem for either of them.
Federal flood maps, which governments use as a guide to determine where to build housing and infrastructure, must be updated regularly. But they often fail to take the full risk – the result of a lack of resources, but sometimes also pushback from local officials who do not want new limits to development.
And as the flooding in Vermont shows, the government can’t focus its resilience efforts in clear areas, near coastlines or rivers.
But the country lacks a comprehensivecurrent, national rainfall database that can help inform homeowners, communities and governments about the increased risk from heavy rainfall.
In Vermont, the real number of homes at risk from flooding is three times greater than what federal flood maps show, according to data from the First Street Foundation, a nonprofit group of research based in New York.
The so-called “hidden risk” is also very high in other parts of the country. In Utah, the number of properties at risk when taking rainfall into account is eight times what appears on federal flood maps, according to First Street. In Pennsylvania, the risk is five and a half times greater; in Montana, four times as many. Nationwide, about 16 million properties are at risk, compared to 7.5 million in federally designated flood zones.
The result is severe flooding in seemingly unexpected places, such as Vermont. Last summer, storms closed parts of Yellowstone National Park, forcing visitors to evacuate. In March, heavy rain prompted federal disaster declarations in six counties in Nevada, the nation’s driest state.
The flooding in Vermont highlights the need to spend more on modeling and planning for flood events, said Mathew Sanders, who leads the state’s resilience efforts for the Pew Charitable Trusts. “You have to look at how the water flows,” he said. “We need to rethink what the most strategic interventions will be.”
All that water often brings tragedy to places least able to handle it.
Last year, a deluge of rain led to flash floods that flooded eastern Kentucky’s valleys. The force of the water tore apart several homes, damaged trucks and blocked remaining buildings with mud and debris. More than 35 people died.
Communities scattered across the Appalachian Mountains are familiar with flooding, with water flowing from streams that flow through the area. But the ferocity of that flood threw longtime families into disarray. “We went from bedridden to homeless in less than two hours,” said Gary Moore, whose home just outside Fleming-Neon, Ky., was destroyed, in the days after the flood.
Floods exacerbated by climate change have also been exacerbated by the lingering effects of coal mining, as industry that once powered communities has retreated, leaving behind eroded hills and mountains that its top is flying. The loss of trees worsened the speed and amount of rain flow.
In Houston, deadly and devastating floods have long been a familiar threat, so the worst storms have become shorthand for marking time: Tropical Storm Beta (2020), Tropical Storm Imelda (2019), Hurricane Harvey (2017 ) and the Tax Day Flood (2016).
But as many as half of the homes damaged by floodwaters in recent years are outside official flood risk areas. An analysis by the Harris County Flood Control District found that 68 percent of the homes that flooded during Hurricane Harvey were outside the 100-year flood, due to surging water in creeks and bayous that flow through the area.
In Summerville, Ga., a city of about 4,400 people nestled in the ridges in the northwest corner of the state, homes and businesses flooded in 2021 after a deluge delivered by the remnants of Tropical Storm Claudette. Most of Summerville is outside the 100-year floodplainand destruction and the result of the purge prevailed over the city.
The flooding has also been a source of frustration and pain in Horry County, SC, a coastal area that includes the resort town of Myrtle Beach. April O’Leary, a resident who started a group called Horry County Rising, said at a 2021 hearing with federal emergency management officials that about half of the homes that flooded in the county were outside. of the designated flood zone.
“There’s really no recovery when you flood,” Ms. O’Leary to the officers. “You haven’t fully recovered financially, and families continue to live in fear of flooding.”
As the threat from flooding and other climate shocks worsens, the federal government has increased funding for climate resilience projects. The 2021 infrastructure bill provided about $50 billion for such projects, the largest infusion in American history.
But that fund is still far below the requirement. This spring, the Federal Emergency Management Agency said it received $5.6 billion in applications for two of its major disaster preparedness programs — nearly twice as many as available.
Anna Weber, a senior policy analyst at the Natural Resources Defense Council who specializes in flood risks, said the government needs to direct more money to the most economically vulnerable communities — the areas least able to pay for resilience projects themselves.
But the scale of the intervention required is also an opportunity to fix old mistakes, according to Amy Chester, managing director for Rebuild by Design, a New York-based nonprofit that helps communities prepare for and recover from disasters. . He said cities and towns can rethink how they build, reclaiming built-up land along rivers, streams and wetlands, and creating new parks or other landscapes to retain rainfall. .
In that sense, he said, adapting to climate change is an opportunity. “When,” asked Ms. Chester, “are you able to rethink how you want to live?”