Evacuation orders and advisories were issued for mountain, canyon and foothill neighborhoods.
Residents can search by address on the county website to see if their area is under any orders. They can also register for emergency alerts on rivcoready.org.
The blaze began as two adjacent fires reported Friday evening in Cherry Valley, an unincorporated area near Beaumont. The cause of the fire is under investigation, but authorities say it likely may be a case of arson.
Crews continue to battle the blaze as scorching temperatures are forecasted in some areas.
Apple Fire evacuation map
How to prepare for a wildfire evacuation
If your household is under voluntary or potential evacuations, begin to prepare your home and get ready to leave. If mandatory evacuations are ordered, it's important to leave as fast as possible.
Here are steps to take to prepare for a wildfire evacuation:
Have a plan
Preparations for a wildfire evacuation (or any emergency) should start before there is any danger. Create a family evacuation and communications plan. Make sure to include pets as a part of the plan. Establish a meeting area outside your home if your house is in immediate danger. Stay tuned to phone alerts, TV or radio for the latest emergency instructions or evacuation orders.
Prepare your home
If there is time to prepare your home prior to a potential evacuation, follow Cal Fire's pre-evacuation preparations list for inside and outside your home. If your family or your home are in imminent danger, evacuate immediately.
Important steps for inside your home include keeping your windows unlocked, moving any flammable materials or furniture away from windows to the center of a room and leaving your lights on so firefighters can see through the smoke.
Important steps for outside your home include gathering flammable items and placing them inside your home, turning off and moving propane tanks away from structures and checking on your neighbors to make sure they are preparing to leave.
Assemble an emergency supply kit
Having supplies for each member of your household is an important step for evacuation preparation. Cal Fire recommends having a three-day supply non-perishable food and three gallons of water per person. Extra eyeglasses or contact lenses, a seven-day supply of medications and copies of important documents, such as birth certificates and passports, are also important to pack.
The Associated Press contributed to this report.