Flood Resilience Depends on Building Capacity for Excess Water

Sarah Kapnick says companies and cities can no longer assume that historical climate statistics adequately describe the conditions their infrastructure, risk models, and operating plans will face. Enough climate change has occurred, she argues, for the statistics of climate to have “separated from the past.”

The earlier discussion was more theoretical in her account: climate impacts were expected in the future, and many people had not yet experienced what those changes meant personally. Now communities face extremes they have not encountered before, while slower changes—including sea-level rise and increased coastal erosion—alter places in ways residents can directly observe.

That lived experience is changing the questions companies ask. Rather than treating climate as a distant concern, they are asking how much additional change to expect, what they need to prepare for, and how to position themselves in a world whose physical conditions continue to shift. Kapnick’s framing is direct: change will continue until emissions go to zero and are no longer accumulating in the atmosphere, so the response cannot be a one-time adjustment.

Al Roker places those decisions amid what he calls “weather weirding”: triple-digit heat, rapidly intensifying hurricanes, a tornado season concentrated in the Midwest rather than the regions more commonly associated with the heaviest activity, and flooding across Utah, the Midwest, and the Northeast. Roker cited 476 reported tornadoes—120% of the 17-year average—with Wisconsin, Michigan, and Illinois above average while areas from Texas through the Southeast and central plains were below average.

Tom Skilling opened with a similarly compressed view of current hazards: Canadian firefighters confronting as many as 900 fires at once; more than 40,000 U.S. wildfires in 2026 burning nearly 4 million acres; unusually warm Atlantic, Caribbean, and Gulf waters; and flooding in Texas Hill Country after more than 28 inches of rain.

For Kapnick, those conditions do not yield a universal climate prescription. Exposure differs by geography and industry, and so do the available responses. But she sees clients revisiting strategies more continuously as science develops, events expose vulnerabilities, insurance reprices risk, and new construction approaches become available. Climate planning, in her account, is becoming a dynamic operating task rather than a static compliance exercise.

Kapnick argues that the language used to describe extremes can obscure the decision problem. A one-in-1,000-year event conventionally means a 0.1% chance in any given year. It does not mean that, once the event happens, a place is protected for the next thousand years.

The shorthand also assumes a stationary climate: a stable system in which the past provides a reliable basis for future odds. In a changing climate, Kapnick says, an event characterized as one-in-1,000-year can become one-in-300-year or one-in-200-year. A one-in-200-year event can occur twice within a decade because the label expresses an annual probability, not a fixed repeat cycle.

The measurements behind those labels are incomplete as well. Kapnick notes that rainfall records are not comprehensive enough to quantify every kind of extreme with confidence. As observing systems improve and more events occur, the statistical picture changes. In the United States, which she describes as among the world’s best rain-gauged countries, updated information is often indicating that extreme events are more likely than previously assumed.

She says a government effort is underway to issue new precipitation data for risk assessment and for engineering systems such as sewers. Her argument implies that planners cannot simply treat historical design assumptions as settled when current conditions and estimated probabilities are changing.

That matters because much existing infrastructure may not be designed even for today’s climate, before considering tomorrow’s. The problem is not merely a greater quantity of rainfall. Extreme flows can expose failure modes that older designs did not contemplate.

Kapnick points to New York as an example. Infrastructure had been designed with pressure from above—the weight and compression from roads—in mind. But when stormwater systems reach capacity, tunnels can also face pressure pushing outward from within. Some tunnels have broken under stormwater pressure, she says, because designers had not anticipated both directions of force at flows once thought implausible.

The practical response Kapnick emphasizes is excess capacity: creating places for water to go when ordinary systems cannot absorb it. In her account, cities facing overwhelmed sewer systems may face a choice between rebuilding those systems and creating additional storage capacity through flood reservoirs and similar infrastructure.

Chicago provides the large-scale example. Beginning in the 1970s, the city built more than 100 miles of tunnels and reservoirs to address a combined network in which stormwater and flows from homes share the same system. During heavy precipitation, that mixture can otherwise enter rivers and potentially Lake Michigan. The system collects excess stormwater, stores it, then pumps and treats it before release.

Kapnick says the project was tested over the Fourth of July weekend, when Chicago received around three inches of rain in a day—approximately a month’s rainfall—and held. The system is being expanded toward the 2030s by roughly 50% in capacity, reflecting both larger expected extremes and a higher probability that they will occur.

The approach need not always be visibly monumental. Kapnick cites New Orleans, where playgrounds have reservoirs beneath them. The land continues to serve its everyday community use but becomes flood-storage capacity when needed. Construction firms, she says, increasingly see this work as a strategic opportunity and are forming specialized floodwater-management teams for public works and large infrastructure projects.

Parking lots, roads, and other built surfaces can become sites for underground retention capacity. The infrastructure remains out of sight in ordinary conditions while providing storage during a flood.

The broader shift Kapnick describes is to treat water management as a design question embedded throughout the built environment. Roker, discussing New York, said older storm drains there were designed to handle roughly 1.75 inches of rain per hour, while rainfall rates now routinely exceed that threshold. A system sized for historical rainfall may not have enough capacity for short-duration downpours.

Sarah Kapnick rejects the idea that a business can solve climate resilience simply by hardening its own facilities. She uses the image of a “Fortress of Solitude”: a company may build a protected site, but that does not help if workers cannot get there during a flood or the surrounding community’s essential systems fail.

Community resilience is therefore part of business resilience in her account. Companies are beginning, she says, to compare the cost and effectiveness of measures they can undertake themselves with actions a community can take collectively. Sometimes a community-scale intervention is less expensive than a company-specific one. Businesses may underwrite such projects or contribute their own skills to help determine what should be built.

The proposition is partly economic. Places that can adapt and implement their plans can become more attractive places to operate, Kapnick says, because they are more likely to remain functional during disasters and through gradual climate change. Resilience can become a competitive advantage rather than only a defensive expense.

Many companies already had business-resiliency plans for extreme weather, she says, but such losses were often treated as isolated “acts of God”—events presumed unlikely to recur while current leadership was in charge. Repeated disruptions have weakened that assumption. Kapnick says executives now ask for a fact-based account of the statistics, the risks, and the organizational capacity required to respond.

The work extends from diagnosis to implementation. At a bank, she says, she can help clients work through the climate problem and then address where the money will come from to carry out the necessary measures.

Her approach reflects work at NOAA, where she spent more than a decade and served as chief scientist. The job required explaining weather and climate information in different settings—from Alaska to Ohio to hurricane-prone Florida—while being clear about what the science indicated and what remained unknown. She carries the same sequence into corporate advisory work: establish the facts, identify the uncertainty, and make decisions despite it.

Readiness is the objective. In a crisis, organizations must work with whatever resources and equipment are immediately available. Before a disaster, they can assess risk, select interventions, coordinate with communities, arrange financing, and build implementation capacity deliberately. Kapnick says that advance planning is often cheaper than improvising in an emergency.

Kapnick calls that habit “climate intuition”: considering climate exposure in advance as an ordinary part of decision-making, then pairing that understanding with an implementation strategy. The practical question, in her account, is not whether every outcome can be predicted. It is whether institutions will use available information to build capacity before the next failure narrows their choices.