HurricanesShould I stay or should I go: timing affects hurricane evacuation decisions
When a hurricane is gathering strength offshore, people in its possible line of fire still need to decide whether or not to evacuate to safer ground. Emergency managers are charged with ensuring the safety of the population. “Prepare for the worst” is probably a good philosophy in most circumstances, but not in the case of evacuation for a hurricane many days away, when the cost of mobilizing is high and the probability of it being needed is very low. The government and media also grapple with not wanting to be unnecessarily alarmist. The correct philosophy is “know what the worst case could be and be prepared to face it if it comes to pass.” When an evacuation order is issued, it’s usually in a very compressed time frame — but that’s ok as long as people are prepared. If people plan three to five days ahead, knowing that there is a small but real chance they will be asked to evacuate and a small but real chance of death if they do not, they can be ready when the definitive order comes in.
In the United States, the 2015 hurricane season begins against a backdrop of other recent extreme weather news. Texas floods and Midwest tornadoes remind us of what water and wind can do. We can take comfort from considerable improvement in hurricane forecast accuracy in recent years. But when a hurricane is gathering strength offshore, people in its possible line of fire still need to decide whether or not to evacuate to safer ground.
As a social scientist, I’ve been interested in what goes into the choice whether to stay or to go, and whether people will have time to leave if that’s what they choose to do. It’s a complex decision that can be a matter of life and death. Why do some people evacuate and some do not? We’re finding that timing can have a lot to do with it.
Getting out of a storm’s path saves lives
Consider the comparison of lives lost due to Hurricanes Katrina and Sandy. Forty-one people drowned from Sandy’s storm surge and thirty-one others died from falling trees and other causes. Katrina killed more than 1,800 people. Over half of the Mississippi evacuation zone residents heeded the call and left ahead of Katrina. That compares with about 30 percent for Sandy, according to my own survey research.
Comparing populations between coastal Mississippi and New Jersey/New York, a storm like Katrina could have translated into many thousands of deaths if it had hit the New York metropolitan area.
It wasn’t evacuation that made a difference in the number of lives saved. The sobering conclusion is that it was just luck that Sandy, hitting a much more populous area, had weaker winds blowing over people trying to evacuate the day the storm arrived. But the next storm through could have much more intense winds. That potential scenario makes it crucial to examine why there was such a low evacuation rate for Sandy – and how to make sure a future situation would have a higher one.
