The 350-mile-long Sierra Nevada is a unique mountain system in the U.S. with its Mediterranean climate, which means four to six months of drought every summer. California's mountain flora is designed to burn and even flourish and regenerate healthier after a fast-moving fire.
Instead, the Rim Fire is killing everything in its path. The understory ignites trees, and wind is sweeping the fire from treetop to treetop in 300-foot walls of flame.
Scientists also expect the impact on wildlife to be severe. The fire has encompassed nearly the entire migratory range of deer in the region, and the burning treetops likely displaced many of the remaining 300 members of a subset of Great Gray Owl along the Yosemite border, said Daniel Applebee of the California Department of Fish and Wildlife.
"Because their population is so small, any loss is significant," Applebee said.
The fire also cut through habitat of the Pacific fisher, a weasel-like animal that is listed for state and federal protections. The fire has fragmented its range, likely leaving it nowhere to expand, Applebee said.
The Rim Fire is the first of any ecological significance in about a decade in the area stretching from the Sequoia National Forest south of Yosemite to north of Lake Tahoe, said Chad Hanson, a forest ecologist and environmental activist who has published a number of papers on the significance and increasing rarity of post-fire habitat in the Sierra Nevada.
Eventually the forest will come back.
"Because we are in such tremendous deficit of this post-fire habitat type, especially in this area, the Rim Fire is a good thing ecologically," Hanson said. "This is not destruction, this is ecological restoration."
The fire approached the main reservoir serving San Francisco, but fears that the inferno could disrupt water or hydroelectric power to the city diminished. On Tuesday the fire moved into the watershed, which increases the chances of sediment runoff this winter.
Yosemite crews continue to keep water on two groves of giant sequoias less than 10 miles from the fire's front lines.
Associated Press writer Scott Sonner in Reno, Nev., contributed to this story.