A New Jersey mom and her 1-year-old son died of carbon monoxide poisoning while keeping warm in a car as the dad cleared snow from around the vehicle, cops said.

Sasha Lynn Rosa, 23, was in the white, four-door Mazda in Passaic with her son, Messiah, and daughter, Saniyah, when the tailpipe became clogged with snow in the blizzard Saturday night, cops said, according to North Jersey.com.

As the mother and children huddled for warmth, the man, who was not identified, told Rosa to start the engine, cops said.

The dad was shoveling for about 20 minutes when he checked on them and found that they were all unconscious.

He quickly called 911 and EMTs responded at around 8:15 p.m., according to police. The mom and son died, and 3-year-old Saniyah was left seriously injured.

A neighbor who stepped outside her home Saturday night described the scene to Channel 7.

“I know that the boy don’t have life because he’s like this and I try and try, and my nephew tried, and premedical tried, those people worked so hard,” said Isabel Carmona. “I tried to help the girl and I put my mouth on the girl’s and paramedics worked so hard to save that kid.”

EMTs rushed the family to St. Mary’s Hospital in Passaic, where the mother and son were pronounced dead, cops said.

The daughter was transferred to St. Joseph’s Regional Medical Center in Paterson in critical condition.

Family and friends were shocked to hear how Rosa and her son died, posting their condolences to a Facebook page throughout the day on Sunday.

“RIP to my cousins Sashalynn Rosa and little Messiah,” wrote Jaylynn Oliveras. “Such a tragic accident. Going to miss you both.”

“May you and your baby boy, Messiah, rest in peace now,” said Jazmine Sanchez. “I’ll keep ur princess in my prayers.”

James Morrissey added, “Nobody deserves to go the way they did . . . Messiah, we all know u gonna keep mommy safe . . . R.I.Paradise.”

A makeshift memorial of flowers and candles was erected in front of the family’s car on Sunday.

The mother and child are believed to be the only deaths in New Jersey attributed to Winter Storm Jonas, which has claimed at least 28 people.

Carbon monoxide is a colorless, odorless gas that hits quickly and without warning.

A Pennsylvania man also died on Saturday night of carbon monoxide poisoning while sitting in his car in Muhlenberg Township.