As much rain fell in a few hours on Thursday as usually lands in a year, and drizzle continued yesterday as officials and rescuers struggled to control the crisis.
The casinos of the Las Vegas Strip took on the unusual role of shelters as the more familiar summer torrent - of tourists in loud shirts and Bermuda shorts - took refuge among the gaming tables and 24-hour buffet restaurants.
The water drowned out the fountains at Caesar's Palace and forced the cheesy Forum shopping mall to close because of rain sloshing around the corridors. "It looked like a beautiful woman who had been crying, and all the make-up was running down her face," a French tourist, Gilles Bloch, said.
In the suburbs, riverbeds turned into raging gushes, laying waste to neighbourhoods. A homeless man was pulled lifeless out of rushing water in a flood channel and a woman died in a three-car crash caused by the water. Hundreds of people were plucked from their stranded cars by passing fire engines and helicopters picked up others from the roofs of vehicles and houses.
Although the rainfall was relatively modest by flood standards - just over three inches - it hit an unprepared city whose infrastructure lags way behind the growth of its suburban developments.
In some places floodwaters rose as much as 14 feet. Las Vegas has a floodwater retention programme but it is incomplete.Reuse content