Within the last 10 years, at least two hurricanes have closed hospitals, and the St. John's Regional Medical Center in Joplin, Missouri, took a direct hit from a tornado, forcing it to rebuild.
But even when a natural disaster doesn't force a hospital to shut its doors, unexpected catastrophes can disrupt operations and finances.
As many have learned by experience, the best-laid plans for emergency preparedness often go awry: generators kicked on by a power outage malfunction in flood waters, or in the case of Mercy Joplin, get sucked out of a building by the wind; evacuations that depend on outside help can't be controlled; storms hinder staff from getting to work when they are needed the most; and even if the hospital isn't directly in the path of a disaster, what happens in a nearby town can swell inpatient and outpatient volume.
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Here's a look at five notable natural disasters and how they've affected hospitals.
California, Summer 2015
Fires, and more profoundly, smoke, have threatened hospitals in drought-stricken California through the summer, where 400 facilities are testing disaster plans.
By early August, the Rocky fire in the northern part of the state had consumed close to 70,000 acres.
Gov. Jerry Brown declared a state of emergency, as drought-weary Californians for a fourth straight year prepared for yet another dry season and its resulting fires.
"We're well practiced at wildfires," said Cheri Hummel, vice president of Emergency Management and Facilities for the California Hospital Association. "We have more of those than earthquakes."
So far, no hospital has had to evacuate, which is always the worst option, Hummel said.
"It's a decision of last resort for many reasons," she said. "They've been told to plan to evacuate should they need to."
In the past, smoke, more than the flames, has prompted evacuations, or at the least prompted facilities to close their vents and filter the air.
Beyond the immediate threat, resources put into water conservation efforts are harder on the smaller providers. Hospitals are exempt from much of the state's mandatory requirements, but as large water consumers, are conducting water audits and adding "green" features especially in outdoor landscaping.
"We clearly have hospitals and health systems that are kind of leaders in some of these areas," said Jan Emerson-Shea, vice president for external affairs for the California Hospital Association, "because they have the resources to commit to these efforts."
Loma Prieta earthquake, Oct. 17, 1989, California
There have been many quakes in California over the past 26 years, and some have been of higher magnitude than 6.9, but the Loma Prieta earthquake of 1989 will long be remembered for its destruction of bridges and roadways that accounted for the majority of the 63 deaths in the quake.
It struck northern California about 10 miles northeast of Santa Cruz on Oct. 17, as the World Series was about to get underway in Candlestick Park in San Francisco.
It affected 51 acute care hospitals in six northern California counties, according to PubMed.gov.
Overall, the buildings performed well, especially those built prior to the Hospital Act of 1972.
Twenty-two hospitals had partial evacuations. A seven-story tower building, constructed in 1927 at Peralta Hospital in Oakland, suffered serious damage and was closed; two stories of the Santa Clara Valley Medical Center had to be evacuated; and the fourth floor of the Watsonville Community Hospital was evacuated due to loss of elevators and exterior windows, according to published reports. Close to half of the 51 hospitals, or 43 percent, reported inadequate back-up power systems; and five sustained total back-up generator failures, according to the PubMed report.
PubMed researchers concluded the earthquake did not cause total hospital service disruption.
The biggest issue reported by the 51 hospital administrators interviewed was a lack of communication, both from inside and from outside of the organization.
Hospital staff said they received inadequate information about the disaster from local government agencies, but some of that may be tied to the power outages.
Hurricane Katrina, Aug, 29, 2005, New Orleans
Few remember that Katrina began as a Category 1 storm when it first made landfall in Florida, killing two people. It was then downgraded to a tropical storm, but stalled in the Gulf of Mexico, gaining strength to a Category 5 hurricane. Its strongest right-front quadrant slammed into the coast of Mississippi and Louisiana as a Category 3 hurricane, devastating the coastal cities of Biloxi and Gulfport and destroying the levee system in New Orleans, flooding the city.
Hurricane Katrina became one the deadliest hurricanes in U.S. history. An estimated 1,836 people died, according to livescience.
Numerous hospitals, including Lindy Boggs Medical Center, the Medical Center of Louisiana, Charity Hospital, and those in hard hit Jefferson Parish, were closed or damaged by storm surge flooding. However, none received more scrutiny after the hurricane than Memorial Medical, where 45 patients died.
Memorial served the poorer population in downtown New Orleans. When the floodwaters knocked out generator power, the sickest patients on the seventh floor sweltered in 100-degree heat without needed ventilators. Staff heroically carried many to safety down flights of stairs in the dark, hand pumping oxygen into patient's lungs.
However accusations soon arose that patients with Do Not Resuscitate Orders were left in the third tier awaiting rescue by boat, which was slow in coming.
At least one nurse -- forced to make life and death decisions -- allegedly gave lethal injections of morphine and other drugs to those deemed too ill to evacuate.
Lawsuits followed, and questions over just how prepared a provider needs to be for a natural disaster, especially when an emergency plan depends on help arriving from outside of the hospital.
Memorial has since reopened as Ochsner Baptist Medical Center.
Charity Hospital recently reopened as University Medical Center New Orleans.
Hurricane Sandy, Oct. 29, 2012, New Jersey, New York
Hurricane Sandy tore up a wide swath of the east coast in October 2012, affecting 14 states and the District of Columbia. It devastated sections of the New Jersey shore and Long Island.
In the United States, 117 died in total.
When it reached New York, it was technically a post-tropical cyclone, but its power forced the evacuation of an estimated 6,300 patients from 37 healthcare facilities, according to the American College of Emergency Physicians.
Two years later, physicians writing in the Annals of Emergency Medicine took a look at what they called the "patient surge" during the storm.
Some facilities received large numbers of patients with no advance notice, and others prepared to receive patients who instead went to other facilities, the report stated.
"Despite robust preparedness efforts, the severity of Sandy caught New York City hospitals by surprise because major hospital evacuations were not anticipated," the report stated. "Widespread power outages forced hospitals to rely on backup generators, which subsequently failed because of flooding. When healthcare facilities evacuated, neighboring institutions received the displaced patients."
However, with Hurricane Katrina still in memory, many of the lessons from that storm, and from Hurricane Irene, which had hit the east coast a year earlier, helped many hospitals to be better prepared.
"Drawing on lessons learned from Irene, hospitals created sleeping quarters for employees, organized meals and planned for employees to remain on site for 72 hours," according to the report.
Anticipating that public transit, bridges and roads might close, hospitals called in their supplemental staff before Sandy's landfall. Hospitals also discharged 10 to 25 percent of patients who could leave, though there was some concern over discharging those dependent on public transportation as flooding shut down the subway system, according to the report.
"These investments were leveraged in New York City's exemplary medical response to Sandy and clearly reflect significant advancements in hospital preparedness," the physicians wrote in the report.
Problems included provider reimbursement for transferred patients. Receiving hospitals incurred significant costs without assurance of how or whether they would be paid.
Those guidelines now exist, the report said.
Other problems not anticipated included the long-term care of displaced patients, the management of dialysis- and methadone-dependent patients, the absorption and credentialing of displaced staff, and the need to access electronic medical records.
As always, communication difficulties were cited, with one surprise finding: "We found that hospital emergency managers consistently reported that their first calls during Sandy were to their counterparts in other hospitals with whom they already had a relationship," the authors said. "Whether first turning to colleagues -- rather than to a central coordinating entity -- is behavior peculiar to this event or to hospital emergency management culture in New York City or whether this behavior is something to be expected in other disasters is unclear."
The report speculated this behavior was the result of a rise in healthcare coalitions, which fostered interpersonal relationships.
Snowstorm, Nov. 2014, Buffalo, New York
No one expected 60 inches of snow, not even in Buffalo, where storms roll in off Lake Erie early and often through a long winter. But a week before Thanksgiving, two to three feet of snow fell non-stop, halting traffic, including the vehicles of many hospital staffers who tried to get to work, only to turn back.
Mercy Hospital was hardest hit by staffing shortages. However, hospitals outside the immediate storm area were also short employees who couldn't get out of their driveways. This included Kaleida Health, Catholic Health, Buffalo General, Millard Suburban, Children's, DeGraff and the VNA of Western New York.
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All elective surgery was postponed and primary care centers were shuttered. Catholic Health set up a staging area at its downtown headquarters where about 200 employees who made it there were shuttled to Mercy via a four-wheel drive vehicle, according to Buffalo Business First.
To ensure against extreme weather events, the U.S. Department of Health and Human Services made it clear it expects hospitals to have plans and procedures in place.
In Buffalo, plans were in place and personnel were trained, according to C.J. Urlaub, president and CEO of Mercy Hospital.
"We have prepared and trained for this," he reportedly said at the time. "There is enough food, medications and oxygen."