4 Children Swept to Their Deaths With Great-Grandparents While Fleeing Harvey Flooding

The tragedy has only begun to unfold.

One Houston family lost six of its members when Harvey's historic flooding swept away four children along with their great-grandparents.

The unthinkable happened Sunday when family members say Sammy Saldivar attempted to drive his kids and grandparents to safety as floodwaters raged around their Harris County home.

Read: How You Can Help the Victims of Hurricane Harvey

After borrowing a van from a family member, Sammy was driving them over a bridge when the water overtook them.

"The water picked the van up, and it was just floating after that," family member Ric Saldivar told KTRK. "It went head first in, and water came in real fast."

Panicked, Ric said Sammy was able to unbuckle his seatbelt before pulling himself out a window. He saved himself by grabbing a tree branch.

Sadly, not everyone was as lucky.

Devy Saldivar, 16; Dominic Saldivar, 14; Xavier Saldivar, 8; and Daisy Saldivar, 6, likely perished along with their great-grandparents.

Ric said Sammy watched, horrified, as the van sank and was swept away before his family was able to climb out.

"That keeps playing in his head," Ric said.

The dentist who employs the children's family member, Esmeralda, who is a dental assistant, started a GoFundMe page to help benefit the grieving family.

Dr. Terri Alani has worked with Esmeralda for about five years and says the whole office is devastated.

"We are all in a group text," Dr. Alani told InsideEdition.com. "I said 'Who's gone?' She writes: They died."

Dr. Alani is hoping social media will help ensure finances aren't an issue as the shattered family begins to put back the pieces.

"There are 6 funerals," Dr. Alani said. "That’s why I am doing the Gofundme... It’s been a nightmare."

The Saldivars are now presumed to be among more than a dozen fatalities linked to the unprecedented weather disaster that continues to have Houston in its watery grip.

Read: Hundreds Plucked From Catastrophic Floods as Texas Officials Plea for Harvey Aid: 'People Are in Need'

Some 11 trillion gallons of water are believed to have fallen on the metropolis since the weekend, leaving thousands stranded in emergency shelters.

As of Monday, the Saldivars are among at least 14 dead, though that number will almost undoubtely go up as the water recedes and the true impact of the storm becomes known. 

Watch: Woman Spots 2 Alligators Swimming in Flooded Backyard as Hurricane Harvey Rages