consumed by flames collapsing 1 of 200 buildings and homes in the path of this wicked wildfire in napa county, california. >> oh, my god! >> reporter: this car that crashed and caught fire could be what started this blaze. the fire now nearly 7,000 acres. 15% of it contained. >> we were pretty active there for a few hours. >> reporter: the driest conditions in history fueling at least 18 western wildfires. three hikers rescued and families across two communities under mandatory evacuations. >> they made me get up out of my chair, turn my tv off and get moving. >> reporter: the flames jumping this dirt road, threatening wildlife and sending these cattle and horses running. what makes this fire in napa county especially challenging is that it's so tough for firefighters to get to it. look at the smoke rising on the from the steep hills and the conditions bone dry. aditi roy, abc news winters,