As it rumbled toward the city, the 35-foot wave of rain-swollen water churned over and onto itself like a giant snowball, swallowing trees, boulders, homes and anything else in its path.
In minutes, the powerful rush flattened homes, uprooted trees and moved buildings hundreds of feet. It left behind 2,209 people dead — including 99 entire families — and 1,600 homes destroyed.
More than 116 years before Hurricane Katrina (search) destroyed New Orleans, a flood in Johnstown exposed the rift between rich and poor, the kindness of strangers and, in the end, the power of the human spirit to rebuild.
"It's more than just a disaster. It was the biggest story of the late 19th century," said Richard Burkert, executive director of the Johnstown Flood Museum (search).
In 1889, flooding wasn't anything new to the approximately 25,000 residents in this valley town about 60 miles east of Pittsburgh. But the heavy rains on May 31 brought on something much more catastrophic.
Fourteen miles away, the South Fork Dam burst on man-made Lake Conemaugh (search). The rock and clay dam, which held back 20 million tons of water, had been poorly maintained by an exclusive fishing and hunting club whose members included industrialists Andrew Carnegie and Henry Clay Frick.
The water barreled into Johnstown, tearing down nearly everything in its path. The city was left in ruins: buildings and homes were destroyed, stunned survivors were stranded on rooftops and fires broke out.
"Then there was nothing left. It was like a beach when it was over. We just stood there and watched it. Everyone was stunned. We didn't know what to do," survivor Elsie Frum, who was 6 years old in 1889, told The Associated Press for a story on the flood's centennial.
There were reports of looting, and some residents formed groups to deputize themselves before the state militia came in two weeks later and took control.
Blame centered on the South Fork Fishing and Hunting Club because it had made changes to the dam. A screen to prevent game fish from escaping the lake trapped sediment, and lowering the dam to accommodate larger carriages proved to be a fatal mistake.
"People knew it was a bad dam. People talked every spring that it was going to break. They just didn't know what the consequences would be," Burkert said.
Most criticism on the club focused not on the dam but on the wealth of the club members. An editorial cartoon in the Chicago Herald showed members drinking champagne while the poor people in the city drowned beneath them.
"The Johnstown flood was not an act of God or nature. It was brought by human failure, human shortsightedness and selfishness," author David McCullough, who wrote a history of the flood in 1968, said in a 2003 interview.
Tales of death and survival, blame and disorder led to more than $3.7 million in donations from around the globe. Famed American musician John Philip Sousa held a benefit concert.
"This was new and fresh and painful for people at that time. This affected Americans in a profound and personal way," Burkert said.
The first help arrived on June 1, followed by the Red Cross and its founder, Clara Barton, who stayed for five months. Nine temporary morgues were set up; 55 undertakers came to help with the dead.
The rebuilding began almost immediately. Rail lines that had been washed out were fixed in weeks. The Cambria Iron Works, the city's lifeblood, vowed to reopen and did.
"Here's a community that faced the worst that man or nature could throw at it, but they were able to put their lives back to normal," Burkert said.
A judge found neither the club nor its members liable for damages. Among the dead, 750 were never identified and buried in a nearby cemetery.
The city survived, and thrived for many years after, though its most recent threat was the decline of the steel industry in the 20th century. More floods would come, too; one in 1977 killed 45 people.
In New Orleans, the floodwaters have begun to recede, yet the cleanup will likely take months, maybe years. The count of the dead continues, and thousands of displaced residents are trying to rebuild their lives.
"It's hard to say," Burkert said, "how history will frame this."