Firefighters battle Peralta Fire in Jurupa Valley

Firefighters worked through the night to stop a fire in Jurupa Valley in its tracks.

The Peralta Fire started out as a 2-acre vegetation fire at about 9:45 p.m. Thursday between Riverside county and city lines in the Santa Ana River bottom. 

About 46 acres in heavy fuels have burned, but firefighters have been able to stop the spread of the fire, which is now about 50% contained. Crews will be on the scene throughout the day to make sure hot spots don't flare up.

The cause of the fire is under investigation.

Fire crews all over Southern California will be on high alert throughout the weekend after a red flag warning was issued to start Friday afternoon. Most of the critical fire weather conditions, which include winds from 15 to 30 mph and gusts of up to 45 mph, will be over the northern Los Angeles County Mountains and the Interstate 5 corridor into Lake Hughes.