New Yorkers were inundated with the news as Ida’s unprecedented rainfall flooded the city.
Photo-Illustration: Bordered; Photos: Tina Keon; Getty Images
It was, from a meteorological point of view, a perfect forecast. “Significant and potentially fatal flooding,” the New York office of the National Weather Service reported on the morning of September 1, as the still choppy remnants of Hurricane Ida moved northeast. “Major impacts of widespread flooding, especially in urban areas and areas of steep terrain” he warned. “Areas that don’t normally experience flash floods could. But after the suddenness and severity of the storm and its flooding became evident, many people began to wonder if this information had been factored into New Yorkers’ decision-making that night. The next morning, as dozens of people were killed in flooded basements and in cars on the roads, New York Governor Kathy Hochul specifically targeted emergency warning systems when she asked what had failed. “Is our communication system adequate to inform people in homes and on subways that it is dangerous?” ” she asked. “Are alerts going on people’s cell phones? How do we communicate? And are we doing a good enough job? Because I’m not going to stay here and guarantee that it doesn’t happen again tomorrow.
Conveying the deadly risk of rapidly rising waters is the biggest challenge of flash floods, says Matt Lanza, meteorologist and editor of Space city weather in Houston, where in 2017 he had to convey the risks of an unfathomable flood forecast during Hurricane Harvey which eventually became the the most extreme rain in US history. “If you go too far, people will ignore you. But if you’re up front right away, they’ll listen to you. Even though New Yorkers had suffered significant flash floods from Hurricane Henri less than two weeks earlier, Ida’s rainfall caused the city’s first-ever “flood emergency”. It’s a newer term, Lanza says, coined by the National Weather Service over the past decade to go beyond a flash flood warning and communicate the emergency. And that’s probably not a term New Yorkers were familiar with. “Sometimes you’re so obsessed with the forecast that you communicate all the weather, but that’s not always what helps people in their exact situations,” he says. He wonders if language similar to Houston’s warnings about Harvey could have been more helpful, suggesting something like “Look, we’ve seen a lot of flooding here, but this is the next level, comparable to one of the. worst events you can ever remember.
It’s also about accurately communicating the danger, as most New Yorkers – not all, but most – receive this information as push notifications on their phones. On the night of September 1, the National Weather Service repeatedly sent wireless emergency alerts to all new phones targeted to a specific geographic area. In addition, the people who had registered Notify New York, the city’s emergency warning system – just over 900,000 New Yorkers, receiving advisories in 13 languages plus American Sign Language – has also received alerts, and as the flooding has subsided intensified, the messages too; Notify NYC eventually sent 29. The overlapping messages from multiple agencies sometimes confused recipients, illustrating a problem with the way information about this emergency was received: In a single six-minute period, some New Yorkers received both a tornado warning alert and a flash flood alert, providing conflicting indications to simultaneously “take shelter now in a basement” and “only travel if you are fleeing a flood-prone area” .
A warmer future with more overlapping climate disasters requires major changes in the way information about extreme weather is shared with the public, says Gina M. Eosco, head of the social science program at the National Oceanic and Atmospheric Administration. “We strive to take our forecasting information and translate risk in a way that empowers everyone to act. It is extraordinarily difficult to do under these circumstances. Eosco sees Ida’s impact as a call to action bridging the gap between physical science, where our ability to predict the movement and intensity of storms has improved exponentially, and the social sciences, which are lagging behind. In the New York City situation in particular, language like “look for higher ground” or “avoid crossing streams” is not particularly effective in helping a densely populated area assess danger, she said. . “Maybe it’s ‘going to a higher floor of your building,’ something with more geographic specificity. »Reporting on the impacts of storms also means communicating the specific risk of rising water levels to an urban public surrounded by impermeable surfaces. “It’s not just this complex equation of what’s possible in our atmosphere, it’s what will happen when it hits the ground,” she says. For New Yorkers, that includes listening to the elevation and terrain and the condition of nearby drainage infrastructure.
Mayor Bill de Blasio, to his credit, had been working long before Ida tried to get this information for New Yorkers. In May, his office released a stormwater resilience plan, a series of preventive measures, both physical and political, to be put in place over the next five years, including maps showing which streets are most likely to be impacted by flooding caused by rain. On Friday he announced the constitution of a working group it would speed up some of those goals as part of the climate-induced rainfall response, a city-wide action plan specifically for flash floods that is due to go into effect within two weeks. Part of that plan, he said, would be to geographically target emergency alerts in specific neighborhoods with a high number of basement apartments, followed by sending door-to-door first responders. to evacuate people. Deborah Morris, professor of urban planning at the Harvard Graduate School of Design and former executive director of resilience planning at the New York City Department of Housing Preservation and Development, agreed that a working group from the mayor could hypothetically focus on specific at-risk neighborhoods using a combination of rent registers, housing data and the city’s census outreach plan. But she is extremely skeptical of an approach that relies on emergency alerts and door-to-door support to help people living in informal housing and naturally suspicious of city government. “Even if locally known people knock, they may not open their doors to them, and when you have an urgent emergency like a flash flood, it won’t work,” she says. “This is not a real solution to the problem, which is the danger of being in a basement where storm water cannot be managed properly.”
Relying too heavily on geo-targeted alerts for certain neighborhoods with low-rise apartments also ignores how rising waters can endanger anyone in the city, says Brenda Phillips, a disaster sociologist at the Laboratory of innovation in crisis technologies. What she would like the task force to focus on is setting up flash flood shelters in safe places scattered around the city, similar to cooling centers that open in extreme heat. Telling people to stay off the roads and subways should come with instructions. “When a travel ban is issued, it means gravity, but the question remains how to make people understand the risks,” says Phillips. “So you have to communicate the risk in terms of other situations because, in a way, if you haven’t seen it, you don’t know how much it’s going to get worse: It is the rain that will flood the subways. Here is a shelter that is not at risk of being flooded. Learn about your elderly neighbor.“A travel ban must also be accompanied by a very clear message to keep workers at home,” says Eve Gruntfest, founder of WAS * IS, a community of meteorologists focused on the societal impacts of extreme weather conditions. “It is not enough to say ‘the subways are closed’. Employers need to tell people that they don’t need to come to work, otherwise people will drive, walk, or try other means so that they don’t lose their jobs. But more travel bans and preemptive closures also mean leaders can sometimes over-correct, says Gruntfest. “There must be a tolerance for close calls where precipitation or expected weather conditions are occurring, but not precisely where or exactly when they are expected.” Remember the parents’ anger when de Blasio closed the schools and then the snow did not come?
And that public learning process is going to be the real challenge for New York, where this flood – and there are more to come – are truly unprecedented, Lanza says. It may mean more personalized alerts with better neighborhood maps and better data visualizations, but it also means putting more social scientists at the table, helping emergency managers craft messages that don’t numb people. people with the same robotic jargon over and over again. “Of course, sometimes you’ll be wrong,” he said. “But the question is, did local leaders get this message across on time? “