This small tweak to California parks could help prevent fires / Controversy over management of Los Angeles fires intensifies / Rain helps Southern California firefighters but sends ash and mud flowing down hillsides / Southern California rain helps firefighters but creates risk of toxic ash runoff / Rain in California helps firefighters respond to wildfires but presents risk of toxic ash runoff / Rain on the way to California will aid firefighters but create a risk of toxic ash runoff / Rain on the way to Southern California will aid firefighters but create a risk of toxic ash runoff / Details on new Los Angeles-area fires / Can't find an air filter amid the California fires? Here's how to build your own