IDYLLWILD, Calif. -

The National Weather Service issued a flash flood warning today for the area where a more than 27,000-acre brush fire has been burning for a week.

The warning, which will remain in effect until 2:30 p.m., covers central Riverside County, including Mount San Jacinto and the Idyllwild area. Heavy rainfall and thunderstorms were developing in the area, according to the NWS.

Burn areas are ``particularly susceptible'' to flash floods and debris, according to the NWS. Residents and motorists should watch for mud and debris, which could block roads, and ``potentially dangerous flooding and property loss could result in areas where runoff is restricted or blocked,'' the Weather Service noted.

According to the U.S. Forest Service, firefighting efforts would be adjusted to ensure firefighters' safety in potential flood areas. The Mountain Fire is about 70 percent contained and is expected to be fully contained Wednesday, according to the Forest Service.