crews launching choppers to keep the fires from overtaking the community of lytle creek, where some residentsate. >> it caught one of my trees, but the tree was alive, so it did not last long. reporter: in kern county, the french fire threatening nearly a dozen communities. >> we are talking fire traveling at 40 miles per hour. that is how quickly it comes down. reporter: north above sacramento, evacuations overnight. and the dixie fire, the state largest in its history, still roaring. crews digging trenches to prevent homes from burning to the ground. smoke from the caldor fire closing on lake tahoe. the plume of black haze forcing vacationers to go home. officials say the top priority is keeping the blaze from overtaking the lake tahoe basin. >> not out of the woods, but we are making progress. reporter: making the battle more difficult, temperatures in southern california, even central california, set to top 100 degrees. we are still weeks away from the peak of fire season. liz: a new study as revealing a disturbing trend that could accelerate the deadly cycle of wildfires we are experienc