UPDATE: Flash Flood Warnings for Redlands, Yucaipa, Calimesa, Mountain Burn, Tahquitz Creek, Andreas Canyon

Update 2:25 p.m. A flash flood warning remained in effect for south central Riverside County, including part of the Mountain Fire burn area, and forecasters issued cautionary language for anyone thinking of driving in areas where hard rain was falling.

Radar estimates showed an estimated 1 to 1.5 inches of rainfall in the past hour as of 2 p.m. near the junction of Highways 74 and 371, east of Mountain Center.

"This storm drains towards the southern edge of the Mountain Fire burn scar . . . so debris flows cannot be ruled out," the Weather Service advised.

"A short period of even moderate rainfall on a burned watershed can lead to debris flows. The highly erodible soils in a burn scar allow flood waters to entrain large amounts of ash, mud . . . boulders . . . and unburned vegetation.

"Within the burned area and downstream . . . the force of rushing water . . . soil and rock can destroy culverts . . . bridges . . . roadways and buildings . . . potentially causing injury or death."

Update 2:10 p.m. Flash flood warnings were expanded before 2 p.m. for areas including Big Bear, Redlands, Yucaipa, the Mountain Fire burn area, Tahquitz Creek and Andreas Canyon.

At 1:30 p.m. radar indicated estimates of more than 2.5 inches had fallen near Big Bear, Highways 38 and 18, with flash flooding likely, according to the National Weather Service.

Further south, radar indicated potential for flash flooding in Anza and the southern portion of the Mountain Fire burn area.

"Watersheds burned in 2013 with the Mountain burn area are particularly susceptible to flash floods and debrsi flows from the rainstorm," the Weather Service advised. "Dwellings . . . roads .  .  . trails . . . and campgrounds located along drainages within or below the burned basins can be impacted by flash floods and debris flows."

The warning area includes but is not restricted to all dwellings, roads, campgrounds and infrastructure in low lying areas of Tahquitz Creek, Andreas Canyon, Murray Canyon, West Fork Palm Canyon, Apple Canyon, Herkey Creek and Coldwater Creek.

Roads that may be affected include South Palm Canyon Drive, Highway 74 between Mountain center and Morris Ranch Road, Apple Canyon Road and Bonita Vista Road.

Update 1:40 p.m. A flash flood warning was issued at 1:29 p.m. Thursday for Forest Falls, Calimesa, Yucaipa, Mentone and Redlands.

The warning was in effect until 4:30 p.m., according to the National Weather Service.

At 1:19 p.m., radar indicated a stationary thunderstorm over the Forest Falls area, north of the San Gorgonio Pass, which will likely produce flash flooding.

Locations in the warning area include but are not limited to Forest Falls, Highway 38 and Interstate 10, Yucaipa, Calimesa, Mentone and Redlands.

Posted 1:20 p.m. A flash flood warning was issued at 12:25 p.m. Thursday for stationary thunderstorms north of Big Bear Lake and Big Bear City along Highways 38 and 18.

The warning was for a time period ending at 3:30 p.m. Aug. 29, according to the National Weather Service.

At 12:10 p.m. radar indicated mostly stationary thunderstorms in the area that would likely produce flash flooding, the Weather Service advised.

A flash flood watch was in effect for Thursday afternoon and Thursday evening in the San Gorgonio Pass, the mountains and recent burn areas.

"Another surge of subtropical air will spread into Southern California during the day on Thursday . . . with scattered thunderstorms likely developing during the afternoon," the Weather Service advised.

"These thunderstorms will be capable of producing very heavy rainfall . . . with flash flooding or debris flows possible. . . . In addition to flash flooding . . . heavy rainfall could cause mud and debris flows in and below burn areas of the past couple of years."

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