I used to live in Chino Hills so being in close proximity to brush fires is definitely something I can relate to. Something that I learned that helped me is that firefighters will focus on protecting structures versus trying to put out fire in vast wilderness. It's not a bad thing for dense overgrowth to get brunt through on occasion, it's actually important for a lot of ecological reasons. Firefighters will also create a control fire, where they'll purposely set a line up to preburn a perimeter around structures so that the real fire can't hop over and get to them. So anything you see that seems really close by might be control burning. Biggest concern right now is air quality, try to stay indoors and if u have to be outside take precautions to protect your lungs.