A balcony collapse sent four people to the hospital Saturday as thousands of revelers flooded Isla Vista for “Deltopia.”

Barred for the fourth straight year from holding the traditional beach bacchanalia known as “Floatopia,” celebrants instead began gathering Saturday morning on Del Playa Drive for a massive street party.

Just before 3 p.m. Saturday, a balcony collapsed at 6643 Del Playa Drive, the senior house of UC Santa Barbara’s Beta Theta Pi fraternity, the Santa Barbara County Fire Department reported on its newsline.

Four people were taken to nearby hospitals for treatment, authorities said. Their conditions were unknown late Saturday.

According to the Fire Department newsline, 20 people were standing on the wood balcony when it buckled in. The cause of the collapse remains under investigation.

Floatopia dates to 2003 and traditionally has been a largely student-run blowout marking the start of UC Santa Barbara’s spring quarter. To ensure public health and safety as well to protect the beach from excessive waste and litter, authorities in 2010 began barring beach access on the April weekends that they expect the event to occur.

To counter the crackdown, organizers moved the beach bash to the blufftop above.

Noozhawk intern Kelsey Gripenstraw can be reached at kgripenstraw@noozhawk.com. Follow Noozhawk on Twitter: @noozhawk, @NoozhawkNews and @NoozhawkBiz. Connect with Noozhawk on Facebook.

Students packed Del Playa Drive and surrounding yards and driveways for Isla Vista's fourth 'Deltopia' celebration. (Kelsey Gripenstraw / Noozhawk photo)

Students packed Del Playa Drive and surrounding yards and driveways for Isla Vista’s fourth “Deltopia” celebration. (Kelsey Gripenstraw / Noozhawk photo)