The U.S. Open of Surfing concluded its nine day competition at Huntington Beach on Sunday, but apparently its fans didn't get the memo. A horde of surfing fans descended upon downtown Huntington Beach after the competition, leading to a full-on riot on the city's normally quiet streets.

In all, eight people were arrested for their actions during the riots. Accounts of violence after the event ranged from damaging city property to assaulting a police officer. Several police officers reported that they sustained injuries during the riot, though none appeared to be serious.

"It really started when a ketchup bottle came from the top story of a bar and exploded," said one witness, Kyle Calder. "Kid didn't know what to do with it, threw it into the crowd. Couple more fights broke out. That's when the cops came, and everything went mayhem from there."

Though police officers were quick to the scene of the first altercation, their presence in turn caused many surf fans to flood into Huntington Beach's downtown area. Their number became too great for the city's police force to handle, and soon, the situation turned ugly.

Several fights soon broke out among the mob amid the panic. At one point a man busted through the window of a local bike shop, and soon the establishment was overrun with looters. Eventually police backup was called in, and they quickly retook control of the city by force.

"We couldn't even see. We were like on the ground hiding behind plants and stuff," recalled another witness, who identified herself only as Allie. "The cops were like hitting people and they had like rubber bullets and they shot some guy in the face like right in front of us. We were just sprinting down Main Street."

In total the riot last only about a three hours, with the last of the violence quelled close to 10 p.m. The Huntington Police Department had to request help from neighboring cities and are now asking for anyone with evidence that could lead to more arrests to step forward with what they have.

"We're extremely disappointed and saddened by the disturbance that occurred up on Main St after the close of the US Open of Surfing. We work tirelessly with City staff, police, fire and other agencies to ensure a safe environment for all. We appreciate the quick response of HBPD and are awaiting further information," said the official site for the U.S. Open of Surfing.

Numerous videos of the riot have already made their way online, including several posted to YouTube. As you can see in the above clip, confusion and aggression were both running high in the crowd. Let us know what you think and comment below.