A drunk 19-year-old girl was seriously injured when she fell off the rooftop of an upper Manhattan building as she peed near the ledge – and her friend later claimed she was blown off the roof by a gust of wind, law enforcement sources said.

Meri Marabyan, and her 20-year-old friend Jesus Plata were visiting their pal Nelson Maldanado, 27, who lives at the five-story building on West 179th Street near Audubon Avenue in Washington Heights at around 11 p.m. on Wednesday, sources said

After the three drank rum and beer in the stairwell of the building, Marabyan and Plata went up one flight to the rooftop to urinate at around 2 a.m., sources said.

The two friends went to opposite edges of the building and peed when suddenly Plata and the Maldanado, who was still in the stairwell at the time, heard a loud thump, sources said.

When the frantic men couldn’t find Marabyan they assumed she fell and in a panic called 911.

Plata explained to cops that she had been swept off the roof by the wind, sources said.

Marabyan, who lives in the neighborhood, was found face down with her pants around her ankles on the roof of an adjacent building two stories below, police said.

Emergency responders rushed her to Harlem Hospital where she was listed in critical, but stable condition, authorities said.

Her blood tested positive for cocaine and alcohol, according to sources.

Investigators believe that she accidentally fell after urinating. A puddle of fresh urine was found on the roof, sources said.

Maldanado’s stepfather, who lives at the building, said that his stepson is “devastated” over the incident and was visiting Marabyan at the hospital.

The man, who asked not to be named, described Marabyan as a “straight A student.”

Additional reporting by Elizabeth Rosner