Five people were killed in flash flooding on a road in eastern Pennsylvania on Saturday evening, officials said.

Two young children from the same family — a 9-month-old boy and a 2-year-old girl — remained missing as of Sunday afternoon. 

The Upper Makefield Township Police Department said in a Facebook post that the family from Charleston, S.C., was visiting family and friends in the area when they got caught in the flash flood. The father, 4-year-old son and grandmother survived, while the mother is among those confirmed dead.

“This has been unbelievably devastating to all the families involved, all of our first responders, and to our community as a whole,” the police department said. “We are all in grieving over the loss of life we have seen.”

“However, our commitment to finding the two children who are still missing is unwavering as we will do all that we can to bring them home to their loved ones,” it added.

Eleven cars were on the road at the time of the flash flood and three were swept away, Tim Brewer, the chief of the Upper Makefield Fire Company, said at a press conference Sunday morning.

Eight people were rescued from their cars and two others were rescued from a nearby creek, he added. 

“In my 44 years, I’ve never seen anything like it,” Brewer said. “We had approximately 6 ½ to 7 inches of rain in under 45 minutes. When the water came up, it came up very swiftly.”