On Thursday evening, February 13, 2025 at approximately 5:02 PM, a torrential downpour struck the fully burned-out Eaton Canyon area. Rain rates of up to 2.04″ per hour were observed by weather station data at the Eaton Reservoir as a rigorous narrow cold-frontal rainband (NCFR) pushed through the Los Angeles Basin. Approximately 22 minutes later at 5:24 PM, a ~12-foot tall, 100-foot wide surge of water and debris emerged from the mountain gorge and entered Eaton Canyon’s wash. The debris flow spread out to roughly 250 feet in width and 5′ in depth after arriving in the wash. The flood took less than 5 minutes to travel between the Chuck Ballard Memorial Bridge and the New York Drive Bridge. With thousands of tree logs in transport, the extreme flow laid waste to several large stands of young Western Sycamores, White Alders, and Arroyo Willow trees. In just that time, the route of the creek switched channels in many locations, burying the previous channel used since 2005 in sediment and leaving once creek-side trees up to 50 feet removed from the new channel.
Observes looking over the fence at Midwick observed the flood pass by at 5:26 PM.
Despite only 3.5″ of rain falling as a storm total, the torrential nature of the rainfall and burned hillsides were all that was needed to trigger the debris flow. However, the duration of the flood was limited due to the lower rain totals, preventing sediment erosion on the side of the wash experienced during other major floods in past decades.
Based on a preliminary view of the park from the various (closed) trailheads looking in, the flood easily ranks in the top-5 largest floods of the past century, approaching the magnitude of the 1969 and 1980 floods. A more formal analysis in the coming months will need to be conducted to determine the full extent of the damage.
Three hours following the flash flood, the creek level had dropped significantly. By the next morning, creek flow returned to a typical rate of flow often seen in winter and spring.
