Family watches on as Texas home destroyed by flood

A US family has watched helplessly as raging floodwaters that killed three people ravaged the lower level of their Texas home.

Sarah Perez, from Wimberley in central Texas, posted a video shot from the second floor of the property overnight.

"Oh no, oh no," an unidentified woman gasps as the torrent bursts through a downstairs door and water pours in through windows.

A man comforts her as a wooden chair is carried away by the current.

The pair briefly fall silent with the lights flickering before the room is plunged into darkness. The woman then begins to sob quietly.

Flecks of light offer only a small indication of the destruction below, as the home's contents become completely submerged.

Two men and one woman have been confirmed dead as more than 150 emergency personnel search for nine others reported missing after heavy rain flooded the state's historic Blanco River on Saturday (AEST).

Earlier, officials said 30 people were unaccounted for, but all have since been located.

Family members have identified eight of the missing as members of two families on holiday in a home swept off its foundations by a "wall of water" and thrust down the river until it smashed into a bridge.

Two six-year-olds and a four-year-old were among those inside.

Sources: YouTube, My San Antonio