ISLA VISTA, Calif. — The scene Monday on Del Playa Drive was a curious, uniquely Isla Vista mix: part laid-back beach vibe, part riot aftermath.
Beach towels fluttered over cliffside balconies as UC Santa Barbara students enjoyed spring weather. Dumpsters overflowed with beer boxes and red cups.
"I was in the riot," one young woman said nonchalantly to her friend as they rode beach cruisers.
"I got hit by a tear gas grenade," a male student told his friends as they carried an inflatable pool over their heads.
They were talking about Deltopia, a social media-fueled street party that spun out of control Saturday night, leaving a sheriff's deputy seriously injured and more than 100 people arrested.
The eruption of violence was nothing new for unincorporated Isla Vista, a densely packed, student-dominated community where the average age is 23 and officials have struggled for decades to curb sporadic bouts of Bacchanalia.
"We've been dealing with this issue one way or another for the last 45 years," Santa Barbara County Sheriff Bill Brown said. "There's been problems and challenges in Isla Vista that don't exist elsewhere in the country."
Last year, authorities received 440 calls during Deltopia, and a visiting student from Cal State Poly San Luis Obispo was found dead in the surf after falling off the cliff.
The estimated 22,000 residents of Isla Vista, 60% of whom are UC Santa Barbara students, often blame incidents on outsiders. But the campus' student president sent an email to students Monday saying that they need to take responsibility.
"Yes, it is true that much of the crime that happens is connected to out-of-towners, but who invites these people into our town?" Jonathan Abboud wrote. "We do. It is perfectly OK to celebrate holidays such as Deltopia, but we must consider that inviting our seven best friends from high school does tend to contribute to the problem."
Like the area's raucous Halloween celebrations, Deltopias are not organized events as much as calls to come and party, now trumpeted on social media.
"We have asked over and over if [backers] want to come forward and take responsibility" for getting permits, County Supervisor Doreen Farr said Monday. "And nobody has been willing to do that.
"It's clear that unsponsored events just have to end," Farr added. "When you have thousands of people congregate, up to 15,000, it's just inviting chaos."
Still, Farr said she saw students out in force Sunday cleaning up, appalled at what happened.
The most serious trouble began about 9:30 p.m. Saturday. Sheriff's deputies were breaking up a fight on Del Playa Drive and trying to make an arrest when one officer was hit on the head with a backpack full of liquor bottles. He suffered a significant head injury and required 20 stitches, sheriff's spokeswoman Kelly Hoover said.
As the officers tried to help their injured colleague, the crowd threw rocks, bricks and bottles at them, Hoover said. Four deputies were injured, and many others were struck.
"The community is still trying to come to grasp that people were throwing objects at our law enforcement who are there to protect them," Hoover said. "It just doesn't make any sense."
Clayton Yantzer, 19, a UC Riverside sophomore, said he came for the party and felt things begin to break down by sunset. Law enforcement presence was heavy and aggressive.
"You've got drunk 20-year-olds that just want to hang out, and all they're being told is 'No, no no,'" he said.
Yantzer watched little moments escalate. A man stole a pizza from a Domino's delivery man and ran, creating a scene. The deliveryman got in his car and a group of revelers piled in behind him as others pounded on the vehicle and tried to tear its sign off. Soon stolen pizza was strewn all over the street.
Michael Holsinger, 19, a community college student from Northern California, said that by 8 p.m., riot police were using a megaphone to order people to disperse. Students shouted back until one officer threw a stun grenade in front of them, causing a wave of people to flee, Holsinger said.
The standoff evolved into a back and forth with police throwing a smoke or stun grenade every 10 minutes or so, Holsinger said. By about 9 p.m., he left and ambled down a parallel street to the east.
There, he saw about two dozen people trying to tip over a van. Once they decided that they couldn't, they bashed windows with bricks, Holsinger said. Others were yanking up street signs and waving them at the police as tear gas filled the air.
"It was just of a mob mentality," Holsinger said. "A frenzy, crazy."
On most days, Isla Vista is a beach town of student apartments. But it is unique in its isolation — campus on one side, ocean and fields on the others. Over the years, the lack of adult supervision has led to recurring incidents of chaos and the finger-pointing that follows.
Students rioted three times in 1970 and burned a bank building to the ground. Halloween celebrations have routinely spun out of control, with fires in the streets and drunk students falling off the bluff, sometimes to their deaths.
In 2001, as revelers crowded the street, a mentally ill freshman floored his Saab at more than 50 mph into a group of students, killing four and critically injuring another.
The precursor to Deltopia — called Floatopia — started about 2004 as a party on the beach. By 2008, as many as 12,000 people showed up for a day that county parks Director Dan Hernandez called "unmitigated chaos." Thirty-three participants required hospital treatment for alcohol poisoning, heat exposure and cuts. Two of them toppled off the cliff.
With no organizers, there were none of the usual amenities, such as portable toilets.
"Without restroom facilities, many attendees simply used the ocean, creating a large concentration of human waste that threatened sea life," the Sheriff's Office said.
The sheriff closed off access points to the beach in 2009, and the party moved to Isla Vista's rowdiest street, Del Playa Drive, to become Deltopia.
Farr said the transitory nature of Isla Vista — with students constantly cycling through — means some residents have little stake in the community, and that needs to change.
"We don't want Isla Vista to be a place where people think they can come to trash it," Farr said.
As it is now, the sheriff is left to deal with the problem.
When UC Santa Barbara installed cameras after a gang rape in February, it gave six to the Sheriff's Office to install in Isla Vista before Deltopia.
Freshman Justin Chen said this created tension in the community: "People got a '1984' type of feel, a North Korea type of feel."
Now investigators are hoping that the cameras will help them identify the worst offenders in Saturday's riot.
Brown said he wants to use social media next year to tone down the party.
"Getting the message out that 'Hey, what happened wasn't cool,'" Brown said. "You trashed someone's home, essentially. I'd like to see it used in a positive way to discourage them from coming next time."
Mather reported from Isla Vista, Mozingo and Serna from Los Angeles. Times staff writer Matt Stevens contributed to this report.