A pregnant mother whose car was swept away by floodwaters as she was on the phone with 911 was found dead with her 9-year-old son on Thursday night in southeastern Pennsylvania.

Pamela Synder, 31, and her son, Preston Dray, 9, were stranded by floodwaters around 4:30 p.m. Thursday, police and family members told NBC Philadelphia. Police attempted to save Synder, who was pregnant, and her son, but the strong current of the floodwaters made it impossible and uprooted police vehicles.

Douglass Township Police Chief John Dzurek said Snyder's car had been swept about a half-mile down a creek by the flood.

The mother and son were discovered Thursday evening after rescue crews, including a helicopter and drone team, searched along train tracks in Douglass Township, about an hour and 20 minutes northwest of Philadelphia.

Snyder was engaged to be married with a wedding planned for September, the family said. Crews are currently working to recover the vehicle.

Southeastern Pennsylvania was hit hard by flooding Thursday, and the National Weather Service issued a flash flood emergency after some areas received more than 6 inches of rain. The rain flooded rivers, caused a sinkhole at a daycare facility, triggered landslides, and blocked access to a local hospital for several hours, according to The Associated Press.