As Deadly Floods Hit America, a Meteorologist Looks Ahead

From our collaborating partner Living on Earth, public radio’s environmental news magazine, an interview by Aynsley O’Neill with meteorologist Sean Sublette.

In recent days, multiple catastrophic flooding events have hit rural communities in the U.S. Heavy rain in New Mexico triggered historic flooding in the mountain town of Ruidoso. Parts of central North Carolina also experienced flooding. And on July 4th, the Guadalupe River in Texas rose more than 20 feet in under an hour, killing more than 100 people. Many more are still missing. 

Sean Sublette is a meteorologist and the owner of Sublette Weather and Consulting. This interview has been edited for length and clarity. 

AYNSLEY O’NEILL: What’s been going on with these incredibly intense flash floods that have been happening across the U.S.?

SEAN SUBLETTE: Let’s back up a little bit: It is summer and it is humid, so flash flooding is not uncommon to begin with. Having said that, because the climate is warming, a warmer atmosphere tends to hold more water, meaning it can evaporate more off of oceans, out of ground moisture, out of rivers and bays, so there is more moisture available to go into clouds and then ultimately back into rainfall—in this case, heavy precipitation. 

We’ve got good evidence from the statistics and the data that the most intense rainfall is actually getting heavier over the past 30 to 40 years. So a flash flood event today is likely a little bit worse than a flash flood event 40 or 50 years ago. So it is not the only thing, but is a contributing factor to the fact that things are kind of getting worse.

O’NEILL: How does flash flood prediction work? How do you predict rainfall, where it’s going to land on, what kind of surface? And how does that all come together?

SUBLETTE: That’s the rub with flash flooding compared to, let’s say, larger river flooding, like on the Mississippi or on the Charles or the Missouri rivers, that’s a very different scale. 

When we think about flash flooding, this is very heavy rain that probably covers a couple of counties or maybe a few square miles, and it lasts for two to four hours or so—something that is shorter in time frame and smaller in spatial scale. And those kinds of things are more difficult to predict than larger-scale phenomena. 

Like in the winter time, most of our weather is driven by larger-scale features in the atmosphere. During the summertime, thunderstorms and the like are driven by smaller-scale phenomena in the atmosphere. When we think about computer models and trying to simulate these things mathematically, they are more difficult to simulate and as a result, they are more difficult to forecast precisely. 

The entire weather community knew that flash flooding was likely. The question was going to be, is it bad or is it going to be catastrophic? We wouldn’t know that until it begins to develop. Normally in a situation like this, you can get two to three hours of warning before the water truly becomes dangerous. 

For example, in Central Texas, the warning went out just after 1 o’clock in the morning, and then it was upgraded to a legit emergency three hours later. I wonder, were the people in harm’s way even aware that they were in harm’s way? Did they understand the risk to begin with? Whose responsibility is that to understand what that risk is? 

This is not to lay blame on any one person, or certainly not to blame the victims, but there is kind of this loss of information from the forecasts and the warnings to the end user to get them to take action. I think that’s where we see a lot of the miscommunication, and a lot of what went wrong is in that process. 

O’NEILL: If you were in charge of revamping how we get these warning events and these alerts all throughout the country, what would be your ideal system for informing people?

SUBLETTE: I don’t think there’s one perfect system at all, because we have a country that is rural. Some places it is very sparsely populated. Some places it is densely populated. Some places the cell coverage is good. Some places it’s non-existent. 

I think having a weather radio and being aware of the forecast every day is important, so you have an awareness of what your surroundings are going to be. If we had a network where everyone was able to have a phone and get a reliable warning, that’s great, but that costs a lot of money. I’m not sure how well that’s going to be received. The weather radios are good, but they’re not perfect either. 

I would tell people what I think most meteorologists would tell you: … Be aware of your surroundings. There was a flood watch, which means conditions were favorable for flooding well ahead of the actual flood itself. There are ways to raise awareness ahead of the event before the event hits. But it’s a question of, does that message land where it needs to land, and what kind of actions are taken once the message is received?

O’NEILL: There have been recent federal budget cuts that impact weather tracking and disaster prevention. How have you been seeing that in your own meteorological experience?

SUBLETTE: I don’t think that stuff has really percolated down just yet, it’s still very new. I would liken it to you’ve got a car and you just start ripping some parts out and you drive the car, it might be fine for a mile, 10 miles or 20 miles, but you know, if you took the lug nuts off the wheel, they might just fall off at any time. I think that’s kind of where we are now. We’re pulling things out of the car, and we’re driving it along, and let’s see what happens.

That’s my concern right now, is we are taking safety nets. We’re cutting holes in the safety nets right now, so we may not notice it right away. I don’t think we can say that this tragedy was a direct result of the budget cuts. But I do think the more you cut the budgets, the more you are raising your risk of tragedy. 

The Weather Service office was fully staffed that night, or there was no shortage of staff working that event that night. One position that I understand was vacant at that office was a position of warning coordination meteorologist. At Weather Service offices across the country, there are more than 100 of them that serve their local communities. His or her job is to literally do just that, coordinate warnings with local officials, county officials, emergency managers. 

Oftentimes, they will get on a call a few hours before an event takes place so that everybody is on the same page: “Hey, we really see a big flood threat coming today or tomorrow, you and your staff in your county or your town should be aware of it,” and that’s kind of how the whole process should start. It’s unclear to me if that happened or not, and maybe it did, maybe it didn’t, but again … this is just ripping another part out of a car before you drive it down the highway.

O’NEILL: Is there anything else we should know?

SUBLETTE: I would say, remain weather aware. There’s weather in the short term and there is climate in the long term. Often, we kind of get locked out of that. We’re not paying attention to what’s going on around us and this is, unfortunately, a very stark lesson in paying attention to your surroundings. Things that have not happened in the past are now starting to happen. 

Be aware of your surroundings. Be prepared for flooding, heat, in ways that maybe you didn’t think of before and pay attention to those warnings—they can save your life. 

I do think it’s important to understand that the climate is still warming, and until we start moving away from fossil fuels for energy generation, transportation and industry, the climate’s going to continue to warm, and we’re going to have hotter days, heavier rain and worsening droughts. We need to be prepared for that, and we need to mitigate and adapt, in addition to trying to curb the warming as rapidly as possible.