Late Monday afternoon, fire officials begin planning their strategy to fight and to contain the Manzanita Fire. The fire had burned 5,000 acres by Tuesday morning. Photo by Ed Sherman, Cal Fire/Riverside County Fire Department

The Manzanita Fire, burning east of Highway 79 in Lamb Canyon, grew to 5,800 acres by mid-Tuesday and was 20 percent contained as of press time.

Currently, more than 1,300 firefighters, including the Idyllwild Fire Department, are combating the blaze. Three helicopters and eight aircraft are providing air attack.

The fire started Monday afternoon. The apparent cause was a traffic collision between two vehicles. Two patients were transported to hospitals, according to a Cal Fire report.

Evacuation warnings for residents between Highland Home Road and east to Highway 243, including the communities of Poppet Flats and Silent Valley, have not been lifted. Residents of these areas should “ready” themselves for a potential evacuation under Cal Fire’s “Ready, Set, Go” evacuation planning.

Voluntary evacuations have been issued for the following roads: Highland Home Road, Longhorn Road, Death Valley Road and Shirleon Drive.

Highway 79’s northbound lane was closed to traffic on Monday. Highway 243 and the southbound lanes of Highway 79 are open.

A Red Flag Warning was issued Monday for many parts of Southern California by the National Weather Service through 1 a.m. Wednesday because of high temperatures, single-digit humidity and 20- to 25-mph winds with gusts up to 35 mph.