The deluge Tuesday caught many by surprise, as it dumped 3 inches of rain in 90 minutes, severely flooding the city's northwest section. Casinos along the Las Vegas Strip saw only light rainfall.
``There was so much water, we couldn't see the sidewalks,'' said Ann Friary, owner of Northshore Learning Tree, a day care center.
Rushing water closed the southbound lanes of U.S. 95 and dime-sized hail pelted neighborhoods east of Las Vegas. No injuries were reported, but authorities said they received hundreds of emergency calls and saved dozens of people.
At least two motorists had to be rescued from the tops of their cars by a helicopter. Four firefighters were rescued from a fire engine that became trapped by raging floodwaters.
At the height of the storms, some 3,000 customers briefly lost power, Nevada Power said, although electricity was restored to all but about 300 within a few hours.
Mayor Oscar Goodman declared a local state of emergency and urged people to stay at home and keep off the roads.
The city's last state of emergency was declared after high water inundated the Strip in July 1999. That storm killed two and caused more than $20 million in property damage.
More thunderstorms were in the forecast for Wednesday, the National Weather Service, said but the most severe storms were expected to remain just outside the area.