(CNN) -- A wildfire scorching Southern California prompted authorities Tuesday to order those in more than 20,000 homes -- most of them within San Diego city limits -- to evacuate.
Those residences are being evacuated due to the Bernardo Fire, San Diego County announced late Tuesday afternoon on its emergency website. As of that time, that fire had burned 700 acres and was only 5% contained, according to CalFire.
That agency said people were being asked to get out of the Fairbanks Ranch area, with an evacuation center being set up at Torrey Pines High School. The county sheriff's department said a short time later that evacuees at that center will be moved to a new one at Rancho Bernardo High School.
Sarah Gordon, a spokeswoman for the county, said calls went out to more than 20,000 phone numbers telling them they were among those facing an evacuation order. In addition to these calls, San Diego County Sheriff's deputies went "door-to-door" Tuesday to make sure everyone in danger got the alert.
Most are within San Diego itself, though a small number of those affected are in an unincorporated section of San Diego County.
There are no known reports of fatalities or injuries tied to this blaze.
The National Weather Service issued a red flag warning for areas around San Diego through 8 p.m. Wednesday. As the agency noted, "a red flag warning means that critical fire weather conditions are either occurring now or will shortly," with strong winds, low humidity and warm temperatures feeding into "extreme fire behavior."
Temperatures in the Southern California city are forecast to peak in the mid-90s Wednesday and Thursday with no sign of rain, before cooling somewhat later in the week.