What Good Is a Definition Without People?

This year’s Climate and Society class is out in the field (or lab or office) completing a summer internship or thesis. They’ll be documenting their experiences one blog post at a time. Read on to see what they’re up to.

Miriam Nielsen, C+S ’18

Screenshot of google search results showing previews of flash flood definitions. (Source: Google)

Words matter.

How we read, define and share information has a massive impact on our lives. Everything from ordering lunch to driving a car runs more smoothly when we all agree—or at least understand—what something means. If the menu says sandwich, but you’re served a hot dog or if the other driver at an intersection thinks a stop sign means go, you’re in for a big a surprise.

For many things, there’s a shared understanding of what’s what. But frequently, I find myself talking to a friend, reading a book or paper, even a watching a movie and realizing what I thought was happening is totally different from the other party’s understanding.

Turns out, it isn’t just me.

For the past month, I’ve been working on a research project with NASA Disasters Program and the International Research Institute for Climate and Society about the scope and scale of global flash flood risk, what we known about the dangers of flash floods and what we’re doing about it.  A big part of figuring out what’ we know is defining what a flash flood even is.

Here’s a quick summary of the current state of flash flood knowledge: there isn’t a universally used definition of a flash flood. And maybe more importantly, there isn’t a well understood or accessible definition for people at risk for flash floods.

The American Meteorological Society calls a flash flood a “flood that rises and falls quite rapidly with little or no advance warning, usually as the result of intense rainfall over a relatively small area.”   Another definition from a paper published in the journal Water Policy says “flash floods (or off-plain floods) can happen practically anywhere. These floods are produced by intense rainfall, usually of short duration. They often occur over a very small area in conjunction with thunderstorms or over a large area during tropical storms.”  And my little sister when asked via text message told me she thinks a flash flood is “when a natural event like a rainstorm or a hurricane causes there to be an excess of water that damages the surrounding area.”

On the surface, these definitions appear relatively similar: We’ve got of a lot of precipitation, all at once, in a single spot. But they’re missing a lot of information and don’t give much of an impression of what a flash flood actually is. That may be because most of the research I read in the first couple weeks of my internship was only from meteorological services and hydrology journals (well, not my sister, she’s a precocious soon-to-be college first year). The farthest I strayed was a few geophysical papers.

I was only reading definitions created by people who think primarily about precipitation (and sometimes the planet’s physics) all day. And those definitions are important! But few if any of the papers I read in those first weeks actually centered around people, which seems like an obvious oversight. After all, a massive amount of water suddenly appearing somewhere is going to have a serious impact on people.

I’d love to claim I recognized the flaw in my research methods right away and immediately corrected course, but nah, didn’t happen. Instead, my supervisors pointed out that all the definitions and resources I had collected were climate-focused, not people-focused.

Frustratingly, capturing the socio-economic, cultural, and people-centered perspective on flash floods was a lot more difficult than finding hydrological definitions. If you type “flash flood definition” or even just “flash floods” into your search engine of choice, I’ll be surprised if a single preview includes the word “people.” And it isn’t any better when only searching academic journals either.

Of course, people-centric definitions of flash floods do exist, but they’re not the information that is readily and easily available to the general public, let alone someone living in an area at risk of flash flood. How long are you going to spend searching for a definition when your phone blares a flash-flood emergency warning? Weeks into researching this stuff, when one of those alerts popped up on my phone, I barely knew what those risks were.

And how useful is it, really, to know what a flash flood is divorced of its impact? Knowing to expect an an unusually high rainfall rate of “equal to or greater than 100mm (3.94 inches) per hour” doesn’t tell you getting in your car and trying to outrun the flood is a bad idea.

If we can’t convey what something actually is, in a way that is makes sense to people, how can people stay safe during a flash flood? Without a well understood definition of a flash flood and clearly communicated guidelines for avoiding danger, flash floods will continue to be one of the deadliest environmental harzards.

What exactly is the best way to define flash floods and communicate their risks?

Hopefully, I’ll have a better idea soon.