Opinion: NYC Needs a New Metric for Warning Residents About Deadly Storms

‘Unlike with heat and cold, there are no clear standards in New York for triggering an emergency notification around rain, and no clear steps in place to ensure the most vulnerable are warned and protected.’

Climate change is no longer a looming threat. It’s here, and on Sept. 1 it killed sixteen New Yorkers. Yet when the remnants of Hurricane Ida flooded New York City, many were surprised—including the city government itself.

But the surprise isn’t surprising. The entire world is waking up to climate change one weather disaster at a time. We have never experienced anything like this. But there are no more excuses; we have to act, lives depend on it. And it is no longer enough to plan long-term for climate change. Now we have to assume the next extreme event is around the corner, and have systems in place to protect people.

In New York, we have learned to plan for storm surges, heat, cold and snow—but not rain. And now we have to get serious about measures to both fundamentally rebuild the infrastructure of our city to deal with extreme downpours over a few hours and immediate changes to our emergency planning.

Senators Chuck Schumer and Kirsten Gillibrand are pushing for $33 million in federal funding to upgrade weather warning systems across the state and the country. They’re right to do so. We need to create an early warning system for flooding. Just like for weather that yields extreme heat and cold, or large amounts of snow, we have the technology to predict and prepare for heavy rain that can kill.

The fact is, the recent rainstorm was predicted and even expected by experts. Our nation’s existing weather technology forecast days in advance that the rainfall from the remnants of Hurricane Ida could create “potentially life-threatening flash flooding,” and over 48 hours before the worst of the rainfall the New York National Weather Service office issued a flash flood watch for the city and surrounding areas. But, unlike with heat and cold, there are no clear standards in New York for triggering an emergency notification around rain, and no clear steps in place to ensure the most vulnerable are warned and protected. This is why the first NWS flash flood warning didn’t come until 6:51 p.m., after the rain had already started, and the flash flood emergency wasn’t issued until almost three hours later, at 9:28 p.m. This is unacceptable. These rainfall risks need to be more effectively communicated in advance to save lives.

On Sept. 1, the city received 3.15 inches of rain in just one hour. It’s a huge amount of rain for our city during any time frame, but within one hour, three inches of rain was deadly. Yes, the city implemented resiliency measures after Superstorm Sandy, but those protect New Yorkers and their property from disasters coming from the sea; they don’t do enough to protect from flooding disasters that fall from the sky. And storms like this, with too much rain during too little time, will keep happening. The Fourth National Climate Assessment found that extreme precipitation in the Northeast has increased by nearly 40 percent since 1900 due to our warming climate. We need an effective metric for determining when to warn New Yorkers.

That metric should not just be a measure of how much rainfall is expected, but a measure over how short of a time frame the rain will fall to determine who is at risk when. Once that metric is reached in forecasts, the emergency plan and public warnings must be triggered at least hours in advance to allow New Yorkers time to become aware of the risk and more adequately assess their responses. 

These systems must account for the intensity of rainfall over short periods. What makes high intensity rain particularly dangerous is that it doesn’t leave time for people to get to safe areas before the floods become unsafe. This is exactly why we lost lives during Hurricane Ida—people asleep in their homes felt the impacts too late to evacuate safely. They needed to be notified hours before the danger, not while or after. Crucially, when the city implements a warning system, it must ensure that those warnings make it to everyone, not just those with smartphones and regular internet access. When low-income New Yorkers are most at risk, they must be prioritized. 

We also already know which New Yorkers are most at-risk from flooding. Low-income New Yorkers are more likely to live in garden and basement apartments where dangerous flooding occurs—and a Yale School of Environment study recently found that the flood risk for low-income housing could triple by 2050. Sara Hamideh, Assistant Professor at Stony Brook University’s School of Marine and Atmospheric Sciences, has found that in general, people of color, immigrants, individuals with limited English proficiency, the elderly, and women are more vulnerable to disaster impacts. Our warning system must be designed to reach those populations and they must also be found and educated about the risk before the next storm.

Finally, as the effects of climate change become more and more prevalent, it’s important that the city and its many communities are able to understand how storms have changed and may continue to change. At Stony Brook University, I lead a Climate Extremes Modeling Group, which uses state of the art models that are able to forecast storms under different climate conditions. We come up with two sets of reality: one where a storm makes landfall under pre-climate change or future climate change conditions, and one with current climate change conditions. Technology like ours can better prepare cities and people for the realities of climate change so they are better able to prepare for and adapt to the unfortunate new normal. 

We can’t afford to be blindsided by the next deadly storm, and we don’t have to be. We can ensure that Hurricane Ida is the catalyst for thorough and effective resiliency measures that can start saving lives well before new infrastructure can be put in place. Climate change is here, it’s time to sound the alarm and to immediately implement climate solutions. 

Kevin Reed is an associate professor and associate dean for research at Stony Brook University’s School of Marine and Atmospheric Sciences.