Powerful storms have claimed the lives of at least six people in the US State of Texas and caused widespread flooding and the cancellation of dozens of flights, authorities say.

The storms lashed parts of the state with heavy rains on Saturday, a day after tornadoes ripped through buildings outside San Antonio.

A tornado swept through Brazoria County near Alvin early on Saturday, injuring at least two people and wreaking havoc on some 25 mobile homes in the community which is 30 miles south of Houston.

Thirty minutes later at 5:30 a.m., a tornado struck the Houston suburb of Friendswood, collapsing the roof of one home. 30 other homes were also damaged, but not severely.

At about 7 a.m., between 10 and 30 homes were hit by a tornado in an area of the eastern Harris County.

On the same day, authorities found the bodies of two men who were swept away Friday in the Austin area. Four others have been killed since Friday.

According to the Weather Service, there were other possible twisters on Saturday in or around La Porte and Friendswood, near Houston.

With flash floods in several parts of the city, Houston firefighters have conducted over 130 high-water rescues since midnight on Friday.