The Statistic That Actually Gets People to Evacuate for a Hurricane

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Hurricane Matthew is expected to make landfall in Florida in the next couple hours. It tore roofs off of houses in Jamaica and led to hundreds of deaths in Haiti. Over 2.5 million people are under orders to evacuate in Florida, Georgia, and South Carolina. “This storm will kill you,” Florida Governor Rick Scott said at a press conference. “Evacuate, evacuate, evacuate,” he said — don’t take a chance. But with every storm, there are people who decide it ride it out; in this case, their flag bearer appears to be Vanilla Ice. So what can get them to stop, listen, and get out of harm’s way?

Pacific Standard’s research maestro Tom Jacobs just highlighted something of an answer. For an Environmental Hazards study published in February, a team led by the University of Delaware’s Sarah E. DeYoung analyzed the survey responses of 284 people living in hurricane-prone areas of North Carolina. They were asked at what thresholds they agreed to evacuate, why they might choose to stay, and what factors would guide their decision-making.

The researchers found that wind speed was by far the statistic people were most likely to cite as the reason for leaving, more than doubling the second-place result. It’s a misapprehension that could lead to catastrophe, they say. Wind doesn’t kill many people during hurricanes. Mostly, it’s drowning — often caused by a storm surge, or the rise of ocean-water levels that comes with the weather event. The National Hurricane Center reports that at least 1,500 people died because of Hurricane Katrina’s surge 11 years ago. “If residents in hurricane-prone areas base evacuation compliance decisions on risks thresholds associated with wind speed while ignoring or deprioritizing storm surge threat, their decisions may put them at greater risk during storm surge events,” the researchers write.

DeYoung and her co-authors don’t get into the psychology of why wind speed is so much more motivating that the storm’s category levels or threats of storm surge. My guess would be that, to paraphrase the linguist-philosophers George Lakoff and Mark Johnson, people are most motivated by the things they can physically relate to, and since miles per hour is a metric everybody’s familiar with from driving, it creates a more visceral reaction than the abstractions of a Category 1, 2, or 3 storm, even if those categories indicate wind speeds. It’s one thing to sound a warning, and another to actually be heard.

The Statistic That Gets People to Evacuate for a Hurricane