AUSTIN, Tex. — Louie Bond called it a tsunami, a surge of water that began late Saturday night with torrential rains in Texas’ Hill Country and raced down the bluff-lined valley carved out by the Blanco River.

By the time it reached the vacation getaways and retiree cabins overlooking the river at Wimberley, some 30 miles southwest of here, the surge was 40 feet high, sweeping away bridges and homes and ancient stands of cypresses as if they were bath toys.

One of the homes held 36-year-old Jonathan McComb, his wife and two children and two other families from their Corpus Christi hometown — nine in all, including at least three children. On Monday, Mr. McComb was in a San Antonio hospital with a collapsed lung and broken bones.