Riverside County officials on Saturday warned residents near burn areas that intense rain next week could cause dangerous debris flows.
Forecasters said remnants of Hurricane Rosa and an approaching Pacific storm would likely bring the first rain of the season for the southwest region of California, estimating about a quarter to an inch of precipitation from Monday night to Wednesday.
Some places could receive higher amounts of rain if thunderstorms develop, the National Weather Service said.
The Riverside County Emergency Management Department urged those living near the Holy Fire, which ravaged more than 20,000 acres in the Holy Jim and Trabuco canyon areas in August, and the Cranston Fire, which scorched more than 13,000 acres in the Idyllwild area in July, to prepare for possible evacuations. The agency’s website has a map of locations potentially at risk.
Earlier, Orange County officials issued a similar warning for residents under their jurisdiction who were affected by the Holy Fire.
Near the coast, surf generated by the cyclone off Mexico was expected to build over the weekend. Weather officials issued a high-surf advisory effective through Tuesday morning.
Rosa’s moisture was expected to expand northward from Baja California on Monday, followed by a low-pressure system from the Pacific that will pull moisture into the state Tuesday.