This week’s flooding in Vermont, in which heavy rainfall caused destruction far from rivers or coastlines, is evidence of an especially dangerous climate threat: Catastrophic flooding can increasingly occur anywhere, with almost no warning.
And the United States, experts warn, is nowhere near ready for that threat.
The idea that anywhere it can rain, 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 rainfall, 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 scrambling to prepare American communities for severe flooding, funding better storm drains and pumps, building levees and sea walls, and raising roads and other basic infrastructure. As seas rise and storms worsen, the most flood-prone parts of the country—places like New Orleans, Miami, Houston, Charleston, or even parts of New York—could easily consume the entire government budget for climate resilience, without solving the problem. a problem for any of them.
Federal flood maps, which governments use as a guide to determine where to build housing and infrastructure, are supposed to be updated regularly. But they often fail to capture the full risk – the result of a lack of resources, but also sometimes pushback from local officials who do not want new limits to development.
And as evidenced by the flooding in Vermont, the government cannot focus its robust efforts only on the obvious areas, near coasts or rivers.
But the country lacks a comprehensivean up-to-date, national precipitation database that could help inform homeowners, communities and the government about the rising risks of heavy rains.
In Vermont, the true number of homes at risk of flooding is three times more than what federal flood maps show, according to data from the First Street Foundation, a nonprofit research group based in New York.
This so-called “hidden risk” is surprisingly high in other parts of the country as well. In Utah, the number of properties at risk when accounting for rainfall is eight times more than 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 much. Nationwide, approximately 16 million properties are at risk, compared to 7.5 million in federally designated flood zones.
The result is severe flooding in what might seem like unexpected places, such as Vermont. Last summer, heavy rains closed parts of Yellowstone National Park, forcing visitors to evacuate. In March, heavy rain prompted federal disaster declarations across six counties in Nevada, the driest state in the country.
The flooding in Vermont highlights the need to spend more on modeling and planning for flood events, said Mathew Sanders, who leads state resilience efforts for the Pew Charitable Trusts. “You have to look at how water is going to flow,” he said. “We kind of need to reimagine what the most strategic interventions will be.”
All that water often brings tragedy to places that can least handle it.
Last year, a deluge of rain touched off flash floods that surged through the hollows of eastern Kentucky. The force of the water tore apart some homes, damaged trucks and clogged the remaining buildings with mud and debris. More than 35 people died.
The communities scattered across the Appalachian Mountains are known for flooding, with water spilling from the creeks running through the area. But the ferocity of that flood left longtime families bewildered. “We went from bedridden to homeless in less than two hours,” Gary Moore, whose home just outside Fleming-Neon, Ky., was destroyed, said in the days after the flood.
The floods exacerbated by climate change have also been compounded by the lingering effects of coal mining, as the industry that once powered communities has retreated, leaving behind bare hillsides and mountains with their tops blown away. The loss of trees worsened the rate and volume of rain runoff.
In Houston, deadly and devastating floods have long been a known threat, so the worst storms have become shorthand to mark 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 breached by floodwaters in recent years were outside official flood risk zones. An analysis by the Harris County Flood Control District (Harris County Flood Control District) found that 68 percent of the homes flooded during Hurricane Harvey were outside the 100-year floodplain, due to surging water in the Creek and Bayous running through the area.
In Summerville, Ga., a town of about 4,400 people nestled in the ridges in the northwest corner of the state, flash flooding inundated homes and businesses last year after a deluge delivered by remnants of Tropical Storm Claudette. Much of Summerville falls outside the 100-year floodplainboth the destruction and the resulting cleanup overwhelmed the city.
Flooding has also become a source of frustration and pain in Horry County, SC, a 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 close to half of the homes that flooded in the county were outside the designated flood zone.
“There really is no recovery when you flood,” Ms O’Leary told officials. “You never fully recover financially, and families are constantly living in fear of flooding.”
As the threat of 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 funding still falls far short of the need. This spring, the Federal Emergency Management Agency said it received $5.6 billion in requests for two of its major disaster programs — nearly twice as much as was 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 – those places that are least able to pay for resilience projects on their own.
But the scale of intervention required is also an opportunity to right old wrongs, according to Amy Chester, executive director of Rebuild by Design, a New York-based nonprofit that helps communities prepare for and recover from disasters. She said cities and towns can rethink how they build, returning to nature the land built on rivers, streams and wetlands, and creating new parks or other landscapes to hold rainfall.
In that sense, she said, adapting to climate change is an opportunity. “When else,” Mrs. Chester asked, “can you rethink how you want to live?”