HUNTINGTON BEACH, Calif. — Bicycle salesman Bert Etheredge locked down the shop where he works and sent customers and co-workers into a back room when he saw a raucous mob moving up the main street of a California beach town after a popular surf contest.

Moments later, the wild crowd yanked out a stop sign and rammed it through the window of the Easyrider shop before stealing a bike.

“It was like a flood of people,” Etheredge said. “A running from the bulls kind of thing.”

More than 100 police officers responded to quell the disturbance on Sunday night in Huntington Beach, the city that bills itself as “Surf City USA,” after a fight broke out across from the beach where thousands of spectators had gathered for the nine-day U.S. Open of Surfing.

The raucous crowd toppled portable toilets, threw items from rooftops and smashed car windows along the popular downtown strip lined with restaurants, bars and surf and skate shops.

Police fired pepper balls and rubber projectiles to break up the melee.

One person was treated for injuries at a hospital after apparently being hit by a flying bottle and one of the rubber projectiles, Huntington Beach police Lt. Mitchell O’Brien said.

Seven people were booked into jail, one for investigation of assault with a deadly weapon after allegedly hitting an officer with a skateboard. Others were being investigated for drunken conduct and failure to disperse. Officers initially detained nine people, but two were released.

“Any time you have thousands of people put together like this, you have the potential for things to go wrong,” O’Brien said.

Property damage could reach tens of thousands of dollars, he added.

Police were sifting through photos and video of the melee posted online and expect to make more arrests.

The U.S. Open of Surfing draws thousands of people every year to Huntington Beach. The event that ended Sunday included surfing, skateboarding and live music.

“We’re extremely disappointed and saddened by the disturbance,” said a statement on the U.S. Open of Surfing website. “We work tirelessly with city staff, police, fire and other agencies to ensure a safe environment for all.”

Shopkeepers say downtown is often the scene of drunken bar brawls and rowdy behavior — but not rioting.

Tracey Boyle, 45, said she wasn’t fazed by the melee in the tourist town where she and her three children from Northern California had come to vacation.

“It’s just something that got out of hand,” Boyle said. “You can’t imagine that it would be at a surf event — they seem too chill to get in that kind of confrontation, but they clearly did.”