The white stretch limo was filled with friends on their way to a birthday party, winding their way through country roads in upstate New York on a crisp fall day.

Then, just before 2 p.m., the converted 2001 Ford Excursion blew through a trouble-prone intersection–setting off a chain of events that killed 20 people, including two sets of newlyweds, and transformed the parking lot of a quaint country store into a scene of chaos and horror.

According to authorities, the limo barreled down a hill, failed to stop at a T-junction, and rammed into an unoccupied SUV in the parking lot of the Apple Barrel Country Store and Cafe in Schoharie, about 40 miles from the state capital.

It was, officials said, the worst transportation accident in the country in almost a decade.

“Twenty fatalities is just horrific,” said Robert Sumwalt, chairman of the National Transportation Safety Board. “I’ve been on the board for 12 years and this is one of the biggest losses of life that we’ve seen in a long, long time.”

The passengers reportedly included four sisters and their spouses and friends.

“They did the responsible thing getting a limo so they wouldn’t have to drive anywhere,” their aunt, Barbara Douglas, told reporters.

“They were wonderful girls. They’d do anything for you and they were very close to each other and they loved their family.”

Witnesses quoted by local TV station News 10 reported the vehicle went flying into a crowd of people outside the popular home and garden store. Two pedestrians were fatally injured and all 18 in the limo were killed.

“I saw a lot of people here at the Apple Barrel out in the parking lot. Then I heard screaming. Then I saw this large van, a very unusual looking vehicle out here in Schoharie in the bushes and really wrecked, hit a tree,” resident Bridey Finnagen told News 10. The store’s managing director, Jessica Kirby, estimated that the vehicle was traveling at “probably over 60 miles per hour” when she spoke with the New York Times.

“The first responders broke some windows to try to get people out. I believe the jaws of life were here on the side of one of the fire trucks,” Finnagen said.

The crash sounded like an “explosion,” Linda Riley, a Schenectady resident who had been sitting in a parked car in the Apple Barrel lot at the time, told the Associated Press.

When she got out of her car, Riley added, she saw a body on the ground.

Other witnesses said several bodies could be seen near the wreckage after the crash, which occurred at the intersection of Routes 30 and 30-A.

Among the dead are 34-year-old Erin Vertucci and her new husband Shane McGowan, according to reports. Vertucci’s aunt, Valerie Abeling, told the Associated Press that the limousine passengers had been on their way to a birthday party, one that her own daughter had been invited to but was unable to attend.

“She was a beautiful, sweet soul; he was too,” Abeling said through tears.

The Apple Barrel store posted a statement on Facebook on Sunday saying employees were “doing our best to cope and grieve” but would be open for customers.

“We are a big family at the Apple Barrel, and part of the bigger family of Schoharie. We cope by being together. And that is why we are open,” the store said. The store had earlier announced that it would be collecting donations for first responders after Saturday’s “horrific accident.”

“Our hearts and prayers go out to the victim’s families, our customers who tried to assist, and our staff who tried to comfort,” Kirby told The Daily Beast in a separate statement.

A GoFundMe page has already been established for the children of two of the victims, according to the Times, and donations have reached almost $12,000.

The crash is the deadliest transportation accident to occur in the country since 2009, when a plane crashed in Buffalo and killed 50 people, the NTSB reported. It’s also the deadliest automobile crash since a Texas nursing home bus caught fire in 2005.

Schoharie Town Supervisor Alan Tavenner on Saturday questioned whether recent improvements to the intersection where the crash occurred had really helped make it safer.

“There have been tractor trailers that have come barreling down that hill and it was a miracle they didn't kill somebody,” Tavener told the Albany Times Union.

Three of those tractor-trailers, Kirby told the New York Times, have rammed through their parking lot and ended up in the field behind it.

In a Sunday statement, Gov. Andrew Cuomo pledged to investigate.

“My heart breaks for the 20 people who lost their lives in this horrific accident on Saturday in Schoharie,” Cuomo said. “I commend the first responders who arrived on the scene and worked through the night to help. State police are working with federal and local authorities to investigate the crash, and I have directed state agencies to provide every resource necessary to aid in this investigation and determine what led to this tragedy.”

The National Transportation Safety Board and state police will conduct separate, but collaborative investigations, that will involve an autopsy on the driver to determine if they were intoxicated, and an attempt to determine if the passengers were wearing seat belts.

“We look at everything,” Sumwalt said. “We cast a very broad net to see what's out there. We conduct very thorough investigations.”

But for victims’ family members nothing will erase the pain. “ Our lives have been changed forever,” Abeling told the Associated Press.