According to NBC4 News:
A water main described as “colossal” break flooded streets in the Beverly Grove area of Los Angeles Tuesday morning.
The broken 6-inch main shot a geyser of water into the air, causing a sinkhole and flooding streets.
“It was colossal,” a longtime resident of the block told NBC 4. “The jet of water was easily as tall as the tree.”
“That’s a stab in the dark when you say, ‘What caused the water main break?’” said Kirk Broyard of the LADWP (LA Department of Water and Power). “But again, aging infrastructure.”