A flood control program that will not be finished for another 25 years prevented widespread disaster from storms that in two hours dumped nearly as much rain as the city usually gets all year, according to flood experts.

The $1.4 billion project is only 20 percent complete, but if Thursday's storm had happened a few years ago, "it would have been a disaster to end all disasters," Las Vegas Mayor Oscar Goodman said Friday.

Two deaths were blamed on the flash floods that swamped cars, destroyed three mobile homes and damaged a casino, businesses and homes throughout the Las Vegas area. Three inches of rain fell in an area that averages 4.1 inches a year.

Police and firefighters rescued 163 people from raging waters. Eight of those rescues were by helicopter.

"I can't begin to estimate what would have happened if these flood controls were not in place," said Gale Fraser, general manager of the Clark County Regional Flood Control District. "I know it would have been a lot worse. Prior to our being here, there was no place for that water to go."

The system consists of 30 massive flood detention basins ranging in size from 10 acres to 80 acres. Fraser said one of the basins collected water equal to an amount that would cover a 400-feet-deep football field.

"That water would have run rampant through the valley," Fraser said.

The basins collect water pouring off mountains surrounding the city, then release it slowly along channels and into Lake Mead.

The flood control project was initiated after devastating floods in 1975 and 1984. About $400 million has been spent so far, and another $1 billion worth of work is planned.

Summer floods are not unusual here, where a downpour of an inch or more can swamp streets and fill usually dry washes that crisscross the valley. Thursday's flood damaged a section of Caesars Palace, forcing operators to close part of its casino until midday Friday.