CALIFORNIA — Tropical Storm Hilary brought heavy rain and flooding to Southern California on Sunday, Aug. 20.

Footage from San Bernardino County shows a powerful mud flow affecting Oak Glen Road in Yucaipa.

Residents were warned to shelter in place and to avoid all unnecessary travel amid the heavy rain.

The National Weather Service (NWS) said that three of its California climate stations reported record-breaking rainfall amounts for the entire month of August from Sunday’s rain alone.

Credit: San Bernardino County Public Works via Storyful

Meanwhile, a Californian hiking enthusiast was on hand to capture what he called the “incredible” moment a mudflow came sweeping through Sheep Canyon, near Wrightwood, California, also on Sunday, Aug. 20, carrying wood and debris along with it.

The footage, by X user @TransverseDream, shows the debris approaching as he and two children react. “Before it started we could hear rocks and logs booming and crashing up in the landslide,” @TransverseDream posted on X, formerly known as Twitter.

@TransverseDream said that he’d been up in the canyon previously, where he noted a “lot of loose soil deposited by avalanches & snowmelt”. He said he was therefore “expecting at least mud flows” from the downpours brought by Storm Hilary.

Credit: @TransverseDream via Storyful