Six people were hurt in the midday accident, which authorities say came just minutes after the runway had been plowed. It was a near-tragic reminder of what pilots have long known about LaGuardia: Its relatively short runways and waterfront location leave little room for error, especially in bad weather.
Passengers said the plane landed hard and then took a sharp turn toward the fence on the edge of the runway.
"It felt like fishtailing in a car," Charles Runel said. "But in a much larger car."
Some tweeted photos of the crashing waves just outside the plane's windows.
"I'm just thankful we didn't go into the water," said Malcolm Duckett, one of 130 people aboard Flight 1086 from Atlanta, which stopped atop a berm on the edge of Flushing Bay.
The plane's wings appeared to be damaged in the crash landing, which authorities said also caused a leak of fuel that was quickly stopped.
Snowfall had dropped visibility to a quarter-mile at the time of the crash, and winds were blowing at 9 mph.
The runway had been plowed minutes before, and two other pilots had reported good braking conditions, said Patrick Foye, executive director of the Port Authority of New York and New Jersey, which runs the airport. It appeared the pilot did everything he could to slow the aircraft, he said.
"The plane did not make contact with the water," Foye said. "Happily, that was not a risk today."
LaGuardia, known for its disconcertingly close proximity to the bay, is one of the nation's most congested airports. It's also one of the most difficult at which to land: Its close proximity to three other busy airports means pilots have to make a series of tight turns to line up with its runways while also going through their landing checklists.
The Delta flight was landing on LaGuardia's main runway, which is about 7,000 feet long and 150 feet wide. On the right side of the runway are a taxiway and terminals. On the left, where the plane ended up, are the berm and the bay.
LaGuardia's two runways are "reasonably short" but still safe, said former US Airways pilot John M. Cox, who's now CEO of consultancy Safety Operating Systems.
At airports with longer runways, pilots glide a few feet above the runway and gently touch down. At LaGuardia, Cox said, "you put the airplane on the ground and stop it."
There's no rule about how much snow or ice leads to a runway closing. Instead, the Federal Aviation Administration requires airports to measure runways during winter storms to assure planes can safely brake: A specially equipped vehicle races down the runway with a computer checking braking action, and if the runway fails the test it must be closed.
On Flight 1086, passengers said there was a surreal calm as the plane bounced and slid off the runway, but some children started crying after it came to a stop. It was only then that everyone realized how close they had come to plunging into freezing saltwater.
Passengers were told to exit over the broken right wing because the rear door was too close to the water. They climbed off the plane dressed in their heavy winter coats and scarves and tromped through several inches of snow.
"As we walked across the runway, it was covered with so much snow that I was wondering: Who decided it was safe to land here?" said passenger Jane Kaufman, of Gainesville, Florida.
Among the passengers was New York Giants tight end Larry Donnell, who said he felt blessed to be safe afterward.
"We were all shocked and alarmed when the plane started to skid, but most importantly, as far as I know, all of the passengers and flight crew were able to exit the plane safely," he said by email.
Atlanta-based Delta Air Lines Inc. said the passengers were bused to a terminal.
The National Transportation Safety Board said it was sending an investigator to retrieve the plane's flight data and cockpit voice recorders and to document damage to the plane.