RIDGECREST, Calif. — Three-year-old River Webb calls them “boom-booms.”

That’s one way to describe a pair of powerful earthquakes that rocked Southern California over the holiday weekend, centered in this Mojave Desert city of 28,000 situated between Las Vegas and Los Angeles.

A magnitude 6.4 hit on the Fourth of July followed by a 7.1 the next day, making for the strongest earthquakes to hit Southern California in at least two decades. They were followed by a string of aftershocks that rumbled throughout the region.

“She was freaked out,” her mother, Jessica Webb, who was putting River and her 1-year-old brother, Julian, to bed when Friday’s quake shook. “We just kind of scooped them up and ran.”

The family spent Friday night outside in a tent that Webb and her husband, Nathan Webb, set up in the front yard as far away as possible from anything that could fall, and they ran an extension cord from their house to power electronics.

Because they were sleeping on the ground, they felt every aftershock.

“She said, Let’s wait for the boom-booms to go down'” before going back inside the house, Nathan Webb said of River.

He said when Friday’s earthquake hit, he struggled to reach the front door of their home.

“It’s like trying to run across a trampoline,” he said.

Nothing was obviously amiss Saturday in Ridgecrest, which is flanked by shrub-covered hills. But many businesses were closed that would usually be open, like Starbucks, Burger King and Taco Bell. The doors of a Rite Aid pharmacy were cordoned off by yellow caution tape, although the drive-through was open for prescriptions.

Ridgecrest officials said only minor injuries were reported, and there were no collapsed buildings or known deaths. One resident staying at a Red Cross shelter described Ridgecrest as a “ghost town,” and others wondered and worried whether another strong earthquake was coming.

Gov. Gavin Newsom declared a state of emergency and said Saturday he had spoken with President Donald Trump, who promised to help with rebuilding efforts.

In nearby Trona, a community of some 1,600 northeast of Ridgecrest in the Searles Valley, the water supply was shut down by the earthquakes. On Saturday, workers loaded cases of bottled water at a distribution center at Trona High School, and the Red Cross was delivering water to neighborhoods.

Brian Tuttle, 65, who lives in the Trona area, said the 6.4-magnitude quake and a strong aftershock did not bother him much. But Friday night’s 7.1 was “the most intense experience I’ve ever had.”

He and his wife held on to each other in their front yard during the shaking , the refrigerator door in their kitchen opened and his heavy Harley-Davidson motorcycle was knocked down. His dog also ran away but was found about an hour later.

“Man, did I have a mess to clean,” he said. “I have one plate, one dinner plate left.”

His newly renovated home was not damaged, but other residents were not so lucky. “Everybody that had a chimney lost their chimney,” Tuttle said.

He said he was looking forward to having the water back on and taking a shower.