- Authorities say a boy acknowledged starting the Cascadel Woods fire by burning pine needles in the dry Sierra Nevada
- The boy faces criminal charges but remains out of custody because he and his family are cooperating, officials say
- A Cal Fire spokeswoman said the fire broke out Wednesday afternoon and is threatening dozens of buildings
- At least 500 people are being forced to evacuate as the blaze rages and fire crews from Sonoma, Lake and Napa counties join the fire lines
- At least 136 structures remain threatened, and more than 200 people were still under orders to evacuate their homes on Wednesday
- The destructive wildfire burning north of Napa Valley has scorched 8,300 acres
PUBLISHED: 14:55 GMT, 30 July 2015 | UPDATED: 02:56 GMT, 1 August 2015