How Climate Change Shaped Hurricane Helene

This is a special Hurricane Helene edition of Shift Key. Our regular programming will resume next week.

Nearly a week after Hurricane Helene made landfall, we are still coming to terms with the scale of its destruction. The storm killed at least 182 people, making it the deadliest cyclone to make landfall in the continental United States since Katrina. From Tampa Bay to Asheville, North Carolina, it caused the worst hurricane-related damage in a century.

Why was Hurricane Helene so bad? Why did it cause such horrible flooding in western North Carolina, South Carolina, Tennessee, and Georgia? And did climate change have anything to do with its destruction? To answer these questions, Rob and Jesse speak with Gabriel Vecchi, a Princeton geoscientist and one of the world’s top experts on hurricanes and climate change. Shift Key is hosted by Robinson Meyer is the founding executive editor of Heatmap, and Jesse Jenkins is a professor of energy systems engineering at Princeton University.

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Here is an excerpt from our conversation:

Jesse Jenkins: One of the things that always strikes me, too, about these sorts of events is, you know, think about a dam or a levy, right? It is resilient to the point where it’s not, right? You can have one more inch of rainfall, and that’s what it takes to overtop the dam, or to flood the river banks, or these kinds of things.

And so we have designed so much of our civil infrastructure for these one-in-100-year events, what used to be one-in-100-year events, right? The design specs were for that infrastructure. And now those probability distributions are shifting, and the kinds of events that can overwhelm the design basis of this infrastructure are much more probable.

And you go, it’s not like this event was 20% more intense, and so the damage is 20% more. It’s a binary thing. You go from something that our systems were designed to handle to something that they weren’t, and they break in spectacularly damaging ways. And that’s what I see when I look at these kinds of events. This is not the first flooding that we’ve seen in Appalachia, right? We have built out a flood control system because this happens in river valleys in the mountains, where water gets concentrated.

But this kind of rainfall event was so catastrophic because it just overtopped all of that infrastructure. And like you said, there’s very little you can do, once the infrastructure is fixed, to prepare once you see a storm like this coming. We have to really rethink all of the civil infrastructure planning that we’re doing, and that’s just going to take so much time and so much investment.

Gabriel Vecchi: Well, but I think you’re getting there to the issue of the time scales, right? So the National Weather Service did a phenomenal job of predicting this. But this could only be predicted on time scales of days. In order to change our infrastructure, in order to find an infrastructure that is better, it’s a question of years and decades, and maybe longer. And I think there, we need to be forward-thinking. It is important to see this as a call to think about what can start doing now so that in 10 years, in 20 years, whoever is in this situation is in a better position to handle whatever’s there.

Part of it, of course, is going to be to improve our forecasts, to make them longer range, more reliable, capture the universe of possibilities that a weather event can throw our way. But part of it is going to be relatively … maybe sophisticated is not the right word — build actual things on the ground that are different, right? Put rebar in concrete places, rethink the way that we site our buildings, rethink the way that we, where we take water up from. And one way to look at that is as a challenge. Another way to look at that is an opportunity.

I went to, initially, to college, I wanted to be an engineer. I wanted to build bridges. That was my, coming out of high school, I want to be a part of building things. And as I was in college, I realized, number one, I couldn’t take any electives. I didn’t like that. But number two, we weren’t really building many things. And it was sort of like, I wanted to build things right now.

We’re in a position where we do need to build things. We should be building a lot of things. This is, in a way, a call to opportunity.

This episode of Shift Key is sponsored by …

Watershed’s climate data engine helps companies measure and reduce their emissions, turning the data they already have into an audit-ready carbon footprint backed by the latest climate science. Get the sustainability data you need in weeks, not months. Learn more at watershed.com.

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Music for Shift Key is by Adam Kromelow.