When disaster struck, whether it was a hurricane, earthquake, industrial accident or terrorist attack, getting the wounded to safety ultimately meant getting them to a hospital. But sometimes a disaster affected a hospital itself, forcing the facility's evacuation. Evacuating a hospital was a consequential event—a major logistical challenge that occupied a large portion of an area's emergency management labor and resources. It also limited or deprived the hospital's community of medical services during a time of crisis.

Events that led to hospital evacuations were either anticipated or unanticipated. Hurricanes, wildfires and chemical spills were anticipated events. For these, hospital staff had hours or even days of advance notice and precious time to implement evacuation procedures. Earthquakes, tornadoes, explosions and hazardous materials exposures were unanticipated events. For these, hospital staff had little or no notice and often had to evacuate patients under dangerous conditions.

There were two types of evacuations: internal and external. During an internal evacuation, patients were moved to the safest parts of a facility. Patients could be moved either horizontally, away from danger zones like windows and compromised areas, or vertically, from one floor to another. During an external evacuation, patients were moved to another facility away from the danger zone. External evacuations were either full or partial. Under partial evacuations, most of the patient population, including those dependent on mechanical ventilators and other equipment, was moved, but patients hardy enough to withstand compromised hospital conditions remained. Evacuations could also be done in sequence: horizontal (away from immediate danger), vertical (to a staging area on another floor) and then from the facility if necessary.

Protocol. Most hospital evacuation protocols provided guidance for the following:

• Assessing a hospital's vulnerabilities
• Preparing an evacuation plan
• Deciding whether to evacuate or shelter-in-place
• Determining an order for evacuating different patient populations
• Marshaling transportation resources
• Identifying facilities to receive evacuated patients
• Repatriating patients when the crisis has passed ^[2]

Many evacuation protocols focused on the immediate responsibilities of staff within a facility at the moment of crisis, including ordering the evacuation. The New York Center for Terrorism Planning and Preparedness (NYCTP) issued guidelines in March 2006: a Hospital Evacuation Protocol for state facilities. ^[3] The protocol enumerated the responsibilities of every staff member from cafeteria workers to surgeons. For example, the hospital security staff's role was to guide evacuees out of the facility and first responders into it, and to maintain communications within the facility and to the outside world.

Time to go. There had been numerous hospital evacuations in the US and Canada in preceding decades. Some of the more memorable included:

• At 6 a.m. on February 9, 1971, a magnitude 6.6 earthquake struck the San Fernando Valley centered on Sylmar, California. Four buildings of the Veterans Administration Hospital collapsed, killing 49. Hospital staff evacuated 300 patients to other VA hospitals using school buses and commandeered vehicles. ^[4]
• Just before midnight on November 10, 1979, a freight train derailed in Mississauga, Ontario. Several propane tanker cars exploded, creating a massive fire. Hazardous chemicals in other tanker cars, including chlorine, prompted officials to order most of the city evacuated. More than 200,000 people were forced to leave, including 478 patients from the Mississauga Hospital. ^[5]
• At 4:30 a.m. on January 17, 1994, a magnitude 6.7 earthquake struck Northridge, California. The Sepulveda VA Hospital lost power and its emergency generators failed. Despite darkness, debris and jammed doors, the hospital's staff managed to evacuate 331 patients within an hour and a half. All told, six hospitals were fully evacuated in the aftermath of the Northridge earthquake. ^[6]

In the first decade of the 21st century, flooding triggered numerous hospital evacuations:

• Shortly after midnight on June 9, 2001, floodwaters from Tropical Storm Allison inundated the ground floor and basement of the Memorial Hermann Hospital in Houston. With all power out, the staff evacuated 406 patients down stairwells using flashlights and backboards. ^[7]
• On June 7, 2008, following days of heavy rainfall, Haw Creek in Columbus, Indiana overflowed its banks. Floodwaters inundated the basement and ground floor of Columbus Regional Hospital. The hospital evacuated 157 patients within three hours. ^[8]
• On June 13, 2008, the Cedar River in Cedar Rapids, Iowa crested at a record 31 feet. Despite the efforts of hundreds of volunteers using sandbags, floodwater filled Mercy Medical Center's basement and knocked out power. That night, staff and volunteers evacuated 176 patients in seven hours. ^[9]

Katrina. One of the starkest examples was Memorial Medical Center in New Orleans. When Hurricane Katrina struck the city on the morning of Monday, August 29, 2005, the hospital lost main power and switched to backup generators. The next morning, floodwaters breached the city's levees and advanced toward the hospital.

A chaotic attempt to evacuate the hospital's 187 patients ensued. Coast Guard and private ambulance service helicopters made repeated trips to evacuate patients. By the early hours of Wednesday, August 31, with 130 patients remaining in the hospital, the floodwaters knocked out the hospital's electrical system. Helicopter flights continued, but many of the weakest patients, including four who had been on mechanical ventilators, did not survive long enough to be evacuated. Medical workers were forced to make the gut-wrenching decision to place dying patients in the hospital's chapel in order to focus on patients with a chance of survival. When rescue workers later entered the hospital, they found 45 corpses in the chapel. Overall, Hurricane Katrina forced 30 hospitals to evacuate a total of 5,048 patients and 22,200 staff. ^[10]

Hospitals and federal, state and local governments regularly honed hospital evacuation protocols, and major disasters that affected hospitals tended to prompt reviews. Hurricane Katrina, in particular, was a wake-up call for coastal hospitals about the threat of flooding from hurricanes. Many hospitals had their electrical systems and backup generators at or below ground level, which left them vulnerable to complete loss of power if their facilities flooded. Long term, many hospitals planned to reconfigure their electrical infrastructures. In the meantime, hospitals with basement electrical systems prepared to combat flooding via sandbagging and pumping. But the threat of complete power loss remained, and with it the need to be able to safely and efficiently evacuate.