(CNN By the time Lenda Asberry and her four grandchildren tried to leave home in the dark of night, rapidly rising floodwaters already were up to the roof, police in eastern Texas say -- too late, it turned out, for a safe escape.

Asberry, 64, and her grandchildren, ages 6 to 9, died early Saturday after being swept away by floodwaters in Palestine, police said. It was part of a system of severe storms that left one other person missing, damaged dozens of homes and threatened more flash-flooding in storm-weary Texas and other parts of the South.

Several inches of rain fell in less than an hour after midnight in Palestine, about a 110-mile drive southeast of Dallas, particularly endangering a group of homes in a low-lying area near a creek -- including the home where Asberry and her four grandchildren were staying, police spokesman James Muniz said.

"The water came up extremely quickly. The people tried to get out, but before they could get out, the water was already at the roof of the house," Muniz said.

"They did make it outside the residence and they were all swept away," he said.

People called 911 as the water rose to that house and a few other homes.

The bodies of Asberry; Jamonicka Johnson, 6; Von Anthony Johnson Jr., 7; Devonte Asberry, 8; and Venetia Asberry, 9, were found after the water receded about three hours later, Muniz said.

In the same county, floodwaters from a creek swept a man away from his vehicle off U.S. 79 shortly after midnight, Anderson County Sheriff Greg Taylor said.

The man, about 30 years old, is missing, Taylor said Saturday.

"The water was rising so he got out of his vehicle. Some folks on the other side of the creek tried to help him, and he didn't make it," Taylor said. "He washed away."