Something happened in New Orleans the week of Aug. 29, 2005, that Dennis Mileti had never seen before in his more than three decades of studying natural disasters and human reactions to them: People were left behind during a mass evacuation.

Emergency managers and other officials can improve their evacuation plans based on lessons from Hurricanes Katrina and Rita.

The retired sociology professor and emeritus director of the Natural Hazards Center at the University of Colorado – Boulder says he long considered it a waste of time to plan for mass transportation to help evacuate a city. His understanding of human nature led him to count on the idea that neighbors would not leave neighbors behind.

But in New Orleans, thousands of people were stranded as the city emptied ahead of Hurricane Katrina and during the flooding that followed after several levees failed. Those thousands apparently had no way out and so the idea of neighbor helping neighbor broke down.

“I never heard of any American citizen who couldn’t evacuate because they didn’t have adequate transportation,” Mileti says.

The precise reason that happened remains to be found. But Mileti speculates that the city appears to have had islands of people so isolated from the mainstream that they couldn’t leave. (Similar “islands,” he explains, existed in New York City early in the 20th century.) It wasn’t a matter of these New Orleans residents not wanting to leave. Instead, thousands of them simply were unable to leave, he says.

One lesson for emergency managers nationwide to take away from the Hurricane Katrina evacuation may be to look for similar pockets of isolated, non-mainstream people and plan for how to get them out of town.

Routine complexity
Evacuating thousands and even millions of people from a city is at once highly complex yet utterly routine. Complex because of the sheer number of people trying to leave at the same time. Here, timing is everything. Evacuations must begin early enough to ensure that everyone who wants to leave is able to move out of danger.

And routine because twice each workday every major American city essentially evacuates itself. Commuters, school buses, truck drivers and not a few soccer moms and dads drive toward their destination, stop for gas and groceries along the way, and generally clog freeways and other roads.

The daily ebb and flow of traffic around cities may be so routine that when an extraordinary event like a mandatory mass evacuation occurs, normal information channels break down and evacuees are left wondering what to do and how to do it.

The potential for a communications breakdown worries Benigno Aguirre, senior faculty associate at the University of Delaware’s Disaster Research Center.

“We are so, so unprepared on this matter,” he says. “We don’t have the warnings or the public education.”

With some emergency evacuations, warnings and public education are routine. Schools and offices regularly have fire drills. And the National Weather Service has improved its ability to issue advance warning and sheltering instruction in the case of tornadoes and hurricanes.

But what would happen if a biological or chemical agent were released in a place like New York City, Aguirre wonders. Then, the proper response may not be a horizontal evacuation out of the city, but a vertical evacuation; in other words, to direct people to go up and away from the danger.

At present, few emergency systems can differentiate between threats and signal a range of responses. The danger, Aguirre says, is that a fire alarm sounding at the wrong time may cause people to evacuate directly into the hazard or threat they’re meant to avoid.

That suggests deploying sensors that are capable of telling the difference among a variety of threats (chemical, biological, radiation and fire) and are capable of sounding a different warning for each. The warnings must be clearly understood by everyone who hears them. In turn, those people will need training so they understand the different warning signals and know what their responses should be.

There’s one major problem, however: human nature. Social scientists know that every evacuation involves a period of hesitancy when people mill about. For example, say the fire alarm goes off at work. Chances are people will gather to discuss what they should do, sometimes shouting over the din of evacuation alarms. Large groups tend to mill longer than small groups.

Aguirre says that studies of the World Trade Center evacuation showed that people in large work groups took longer to evacuate than people in smaller work groups.

Researchers found that people in large work groups sought out more opinions before they acted, sometimes with fatal consequences.

Andrew times 10
Even in Katrina, trained professional responders failed to heed evacuation warnings, choosing instead to ride out the storm.

A Galveston Independent School District police officer helps a family of evacuees board a bus at a community center in Galveston in late Sept. 2005.

In some parts of Mississippi firefighters did not evacuate, says Chief Barry Baker of the Ormond Beach (Fla.) Fire Department. As chair of the Florida State Emergency Response Committee, Baker deployed to Mississippi, along with 620 other Florida firefighters, to help with hurricane recovery. He says those firefighters who didn’t evacuate ahead of Katrina knew better, and that some even lost family members as a consequence of their inaction.

“We’re looking at a storm surge as much as 24 miles inland and an average storm surge of six miles,” Baker says. “I would say this is [Hurricane] Andrew times 10.”

Florida’s strategy includes a staged evacuation that begins with a mandatory tourist evacuation from threatened areas, followed by a voluntary evacuation of residents and ending with a mandatory evacuation of everyone remaining.

In heavily populated areas such as Miami, Dade and Broward counties in southeastern Florida, evacuations sometimes need to begin 72 hours in advance of an expected hurricane. A lot can happen to a hurricane in three days, so risks inherently come with the decision to order an evacuation so far in advance
 
“It’s not popular, but that’s how it has to go,” Baker says. When four hurricanes struck Florida in succession in 2004, as much as 85% of the affected population heeded evacuation warnings. It then became relatively easy for police and fire responders to evacuate as many stragglers as possible.

Even so, “most people want to wait until the last minute,” Baker says. The longer the delay, however, the greater the likelihood that food and gas will be scarce and that roads will be clogged.

Travel and traffic  
Transportation issues are emerging as a major after-action agenda item in Texas, where scenes of massive traffic jams were broadcast nationwide as Hurricane Rita approached. Jimmy Sylvia, who serves as judge and chief administrator in Chamber County, Texas (which includes the city of Baytown), says a friend needed 27 hours to travel 35 miles through the congestion.

Sylvia doesn’t think that contraflow traffic lanes on major highways were opened early enough in the evacuation. Even so, he estimates that 90% of his county’s 30,000 residents evacuated in about 24 hours, mostly in private cars.

Testifying in late September before the Senate Homeland Security Committee, Harris County judge Robert Eckels was quoted as saying that disaster plans in his county, which includes Houston, were “overwhelmed” by the 2.5 million people who fled in advance of Hurricane Rita.

In response to the gridlock, Texas Gov. Rick Perry appointed a Task Force on Evacuation Transportation and Logistics in September. The task force is chaired by Jack Little, former president and CEO of Shell Oil Co., and was set up with the support of Eckels and Houston mayor Bill White.

“Hurricane Rita highlighted the tremendous challenges associated with evacuating a major American city,” Perry said in announcing the task force. “While we achieved the ultimate goal of moving millions of people to safety in a matter of hours, we can and we must do better the next time we are faced with an emergency.”

New Orleans’ well-publicized problems and the Texas traffic snarls masked the fact that evacuations in both places were largely successful.

Aguirre calls the Katrina evacuation a “huge success” which demonstrated that local and state emergency management officials learned from problems encountered last year during Hurricane Ivan. The “fatal flaw” in New Orleans, Aguirre says, may have been a failure to plan broadly enough for the community’s diverse needs. “Any emergency management plan will realize that the population is not the same” and that some number of people will need “special care and concern,” he says.

Away, but also up 
That realization led officials in Milwaukee in mid-September to begin drawing up a mass evacuation plan, the city’s first since the Cold War. Mayor Tom Barrett ordered officials to craft a plan that uses public transportation. Presiding over one of the economically poorest cities in the country, Milwaukee officials appear intent on avoiding TV footage of residents being rescued from rooftops by helicopter.

Disaster planners know that the greatest threats are tornadoes, flooding and chemical accidents. By November, city and county officials had begun to focus on two areas of their evacuation and shelter plans: transportation and special-needs populations.
 
Efforts were under way to find buses and drivers to help in a mass evacuation. A related effort had county fire chiefs working to identify special-needs people and nursing homes that might need help evacuating. Local chiefs are also looking at public housing to identify people who may lack the means to get out of town on their own. (Officials also are working to expand the capacity of emergency shelter sites.)

A statewide assessment of disaster preparedness showed that Wisconsin’s 12 largest cities could handle small- to medium-sized evacuations, but would be unable to support a large-scale evacuation. Gov. Jim Doyle directed officials at Wisconsin Emergency Management to help local governments correct their shortfalls. The agency is expected to issue benchmarks and performance standards to help in the process, and officials plan to stage a training exercise in the future to test evacuation plans.

Another lesson is that emergency managers should consider vertical as well as horizontal evacuation strategies. For example, a flood-prone city could build a hospital specifically designed to be self-sufficient in a disaster. Dennis Mileti suggests that such a facility would have a parking garage on its lower floors, an emergency power generator on, say, the fifth floor, and patient rooms and facilities above that. In the event of a flood, the hospital would remain operational.

Evacuation issues may need to be addressed sooner rather than later. Scientists are debating whether global warming is to blame for the seemingly more intense and frequent storms, or if this is part of a more predictable cycle of heightened hurricane activity. Baker says that even a 1°f increase in Atlantic Ocean temperatures can cause a more intense storm.

"It's a new era," he says.

Evacuation plans remain a necessity in every major city, Mileti says. If further research confirms his suspicion that a percentage of New Orleans residents had no means to evacuate, then every city should look for similar isolated and segregated populations who may need extra help.

“It’s not acceptable to leave American citizens behind because they lack resources,” Mileti says. “That’s why we have government.”