Summer thunderstorms triggers mudslides and flash flooding in San Bernardino County, California

Heavy rainfall from the remnants of Tropical Storm Mario on September 17–18, 2025, caused widespread flooding, mudslides, and debris flows in San Bernardino County, California. The event resulted in one confirmed fatality, multiple water rescues, property damage, and road closures across mountain communities.

Authorities reported the death of a two-year-old boy in Barstow after the vehicle he was traveling in was swept away by floodwaters near West Main Street and Lenwood Road. His father was rescued and hospitalized, while the child’s body was later recovered from a flood control channel.

Emergency crews conducted rescues for stranded motorists along State Route 38 near the San Bernardino National Forest. At least ten people trapped in six vehicles were pulled to safety after flash floods and mud cut off escape routes.

Communities such as Forest Falls, Oak Glen, and Potato Canyon were severely impacted. Mud and debris flows carried trees, rocks, and soil into residential areas, with deposits reaching rooftops in some cases. Several homes sustained structural damage, and cars were surrounded or swept away.

Oak Glen Road between Chagall and Potato Canyon was closed after heavy debris blocked the route. Portions of Highway 38 were also washed out or obstructed, and power lines were downed near Yucaipa. Crews from Caltrans and local fire departments were deployed to restore access and clear debris.

Officials emphasized that burn scars from recent wildfires increased the severity of the disaster by reducing slope stability. The National Weather Service issued flash flood watches during the storm, and local evacuation warnings were activated and later lifted as conditions eased.

San Bernardino County agencies continue to monitor the aftermath while cleanup and recovery operations progress. Authorities caution that further storms may trigger additional slope failures in the affected areas.