Authorities said the woman in her 30s and her young son were swept away for approximately a half mile while they were inside their car when heavy rains flooded the area.
Police said around 4:30 p.m. the woman reported being stuck inside the car with her son in the area of Grist Mill Road Locust Road, near Ironstone Creek, in Douglass Township.
She told authorities the water was rushing inside the vehicle and they were unable to escape.
The woman was on the phone with dispatch for 49 minutes while rescue efforts were underway. But rising water even prevented the crews from getting to the mother and son.
The operator eventually lost contact with the woman. The two were later found dead.
Early Friday morning, crews were still on the scene trying to recover the vehicle that remained in the floodwaters.
The identities of the woman and her son have not been released.
The National Weather Service issued a flash flood emergency for parts of eastern Pennsylvania after more than six inches of rain dumped onto the area, flooding roads and trapping motorists in cars.
422 IN DOUGLASSVILLE.— Adam Joseph (@6abcadamjoseph) July 11, 2019
Water is up to the top of the concrete median. Please be careful traveling this evening with many flood warnings and some flood emergencies. Thank you Barbara for taking this pic on the safe side of the street pic.twitter.com/DZ9xMl1fP6
Rescue efforts were also underway in the Pottstown area as water filled the roads.
A portion of West King Street was completely submerged. A car could be seen nearly underwater, but fortunately, there was no one inside.
Trisha Cooney captured a steady stream of water flowing down her road on Hoppenville Road in Green Lane, Pennsylvania.
Over on Middle Creek Road in Gilbertsville, Action News came across Amanda Wickman, who spoke to us on her phone as she walked toward our cameras.
"I was driving home from work in Blue Bell and it started raining really, really hard," Wickman said.
She said once the water began to rise, she knew she couldn't beat it so she found shelter with some friendly strangers.
"This very nice family came outside, brought me into their house, and I've been hanging out there ever since," said Wickman.