When floods hit, getting clear, timely warnings out to people becomes lifesaving, but too often these messages fail. The BBC asks disaster experts about how to get it right.

In the Texan town of South Bend, people used to mark on a concrete pillar where floodwaters had reached in the past, disaster communications expert Keri Stephens recalls.

"It served as a reminder that water has been this high before. These visual warnings and community memories are very powerful," says Stephens, a professor at the University of Texas in Austin. Now, she says, the watermarks have faded.

Texan communities have long had to live with the threat of flooding, which is becoming worse with climate change. When fatal flash flooding hit the state in 2025, questions were raised about whether adequate flood warnings had been provided. While warnings did go out, some residents said they did not understand the seriousness of the situation. For some in the hardest-hit areas, the warning alerts were delayed. Others said that they didn't receive any warnings at all, according to the New York Times.

Alerting people about floods in time for them to act plays a critical role in saving lives and evacuating communities. Of course, warnings are only one part of protecting people from disasters: weather forecasting, long-term resilience measures and emergency responses are also incredibly important. But getting the messaging right about the risks and what to do is a crucial part of the puzzle. Sometimes all it takes is a shift in focus, says Stephens who has found that some people are more likely to respond to a call to protect their car than themselves.

With climate change making floods more frequent and intense, the BBC looks at what it takes to get these messages right, and save lives in the process.

The challenge of getting the right messaging can be particularly difficult for floods. "We're not taught in schools about responding to floods," says Stephens. "In the US, it is common to have 'stop, drop and roll' drills for fires, but we don't have drills for flood warnings."

Rising floods

Floods are the world's most common natural disasters, and their number is increasing. From 1980 to 1999, there were 1,389 major flooding events; this almost doubled in the next 20 years to 2019.

In the US, the National Weather Service (NWS) issues six different types of flood warnings, from "flash flood watch" to "flood warning". These reflect different types of risk at different severities.

Existing flood warnings can be confusing, says Joseph Trujillo-Falcón, a professor in the department of climate, meteorology, and atmospheric sciences at the University of Illinois Urbana-Champaign. "If we're taking all this time trying to make sense of what [the warning] even means, it can delay protective actions and not encourage as many people to seek shelter when needed. We need more plain-language statements that really outline the hazard and get straight to the point."

Research testing warning messages shows they are most effective if they include several critical components: a clear description of the hazard, information about the specific location, and concrete guidance on how and when to act. They also must come from what is seen as a credible source.

"We need to be more precise with our geography [in warnings], especially in areas with mixed topography," says Stephens. Messages should also make it clear that they are only being sent to communities at risk, rather than the entire region.

The key thing, Stephens adds, is for warnings to tell people whether they should evacuate or stay where they are. "One of the big challenges we have with floods is that when sirens go off,........

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