You May (Not) Attempt to Ford the River: Monsoon Edition

Photo: Erik Rakestraw, 2017

We’ve all seen it on the evening news: cars trapped in the middle of a flowing stream created by heavy rainfall that transformed a once safe route into a hazard, a torrent of muddy water surrounding a hapless driver being rescued by first responders. Some of us may shake our heads disapprovingly, wondering why anyone would do anything so obviously dangerous. We might commiserate, knowing that there’s just one road leading to your neighborhood and it too floods out.

Some states, including Arizona, have even enacted a “Stupid Motorist Law” that makes the motorist pay for their rescue if they are stranded after driving around barricades to enter a flooded stretch of roadway. While this law may seem to nudge citizens to take fewer risks, it doesn’t consider the whole picture. No one really wants to identify himself or herself as a “stupid motorist,” and it’s likely that we do know the risks of crossing flooded streets, but many of us do it anyway. Why?

Ashley Coles

I recently sat down with Ashley Coles, a researcher and Assistant Professor of Geography at Texas Christian University to discuss a part of monsoon storms that affect pretty much everyone in the region—the flooded streets we encounter while driving or biking around town. Ashley’s research focuses on the interactions humans have with their environment, especially in the management of environmental hazards and water resources under climate change. Ashley received her PhD from the University of Arizona, and was back in Tucson for the monsoon season.

Sonoran Institute: What brought you to Tucson this summer?

Ashley Coles: I’m following up on my Masters’ degree research, which asks why people continue to drive through flooded roadways. Floods are the second highest weather-related cause of death in the country, with heat being the highest. About 50% of these deaths occur in a vehicle or trying to escape a vehicle. I am surveying Tucsonans about how their routes and habits change during monsoon storms. So far, 65% of people surveyed say they have to drive through flooded areas during their regular commutes to work or school, or regular errands and visits. I am looking at the motivation of people deciding whether or not to drive through a flooded street. Is it a decision that depends on the situation—like making an urgent trip rather than a leisure trip? Do people make different decisions if they are headed to work, to pick up children, or trying to make an appointment on time? Are there cultural differences in seeing the action as safe or unsafe?

Sonoran Institute: Do summer storms impact different demographics in different ways?

Ashley Coles: I don’t have enough data to say for sure, but it’s clear that pretty much everyone is affected in some way. We have flooding in low-income areas, middle-class areas and on the access roads to wealthy areas in the foothills or suburbs. Many neighborhoods simply don’t have alternative routes to take. The City of Tucson has mapped about 400 signs warning, “Do not enter when flooded” but we know there are many more streets that flood than are marked. People in every age, ethnic, and class category are having to deal with floods. Once the data in my current study have been processed, there may be enough information to say whether certain groups are disproportionately affected.

Sonoran Institute: Why do people continue to drive into flooded roadways?

Ashley Coles: The key factor people mention is that the car in front of them went through and made it. People look to see how deep the water was on that vehicle and how fast the water is flowing. I believe that people generally do understand the risks, and want to make the right decision. In my previous study, 64% of people said they have had at least one situation where they decided not to cross. 90% said that danger is a strong influence on their decision not to cross, and 77% worried about damage to their vehicle. People rank having family on the other side of a flooded street as the second highest reason they will cross. Not knowing an alternate route also has an influence on people’s decision to cross, especially for women.

Or, it can simply be very dark out, and a person doesn’t realize they’re in the water until they are. Most people use the signs and barricades as an indication of possible danger, so if there isn’t one they are more likely to drive through.

People say they will test the depth and flow of the water by throwing a rock, or use a stick to gauge it, but it’s important to realize that the situation is inherently difficult to judge. It isn’t that people who drive through are completely unaware or are big risk takers. People make the judgment every time they come upon a flooded road, and sometimes it’s a bad judgment that results in damage to the vehicle or even death. It also doesn’t help that you can be doing fine driving across, but then a wall of water comes rushing all at once. Your best judgment can’t take that into account, so it’s best to avoid crossing flooded roads.

Photo: Erik Rakestraw, 2017

Sonoran Institute: How do we help people avoid these dangers?

Ashley Coles: There are some interesting technologies available through mapping websites, like, (under construction), and Pima County Regional Flood Control District ALERT website, which has rainfall and stream flow data. The key is to integrate these with navigation apps that could tell people where it is flooding and offer alternate routes. In places where there aren’t alternate routes we need more investment in storm water control.

Adding flashing lights to the warning signs during storms can help alert people more effectively because it tells you that it’s too dangerous right now. Otherwise, if the signs are up all the time, you have to make that judgment yourself. Some places already have flashing lights, like underpasses and some of the larger washes.

Another thing that is really important is to spread the word to people who are new to Tucson. So many people said they got stuck when they first moved here.

Stalled vehicles at Park Ave. & Adams St. Tucson, AZ. Photo: Ashley Coles

Sonoran Institute: Do you have any surprising stories from your research?

Ashley Coles: There is an assumption that it’s mostly men driving through, but in my previous study the rates of men and women deciding to cross are the same. What’s also interesting is that less confident men are more likely to drive through flooded roadways than more confident men, whereas confidence doesn’t seem to be a factor for women in this case.

In my current study, I’ve also been surprised by the number of people who just accept the floods as part of living here, and don’t really get annoyed by the inconvenience. Many people say, “We just don’t drive when it rains.” If you don’t have to go somewhere urgently, it’s a good opportunity to sit back and enjoy the monsoon storms.

Covered wagon or family sedan: don’t attempt to ford the river!

Blog Post By: Corinne Matesich, Marketing Communications Coordinator