SAN DIEGO — San Diego lifeguards closed off parts of Black's Beach after a large rockfall Thursday morning.

Emergency vehicles were used to prevent beachgoers from accessing some of the more unstable areas.

black's beach collapse
San Diego Lifeguards

Since the cliffs are made of sandstone, they are extremely dangerous and unpredictable, according to lifeguards.

Lifeguards warned beachgoers not to sit up against the bluff if visiting Black's Beach.

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