For a century, humans managed to tame the Sierra Nevada, investing immense effort and ingenuity to snuff out the wildfires that used to blaze through its forests.  Loggers were able to go about their business without disruption, and settlers were emboldened to build homes in ever more remote areas. It was man versus nature, and man, it seemed, had won.  That conceit is currently going up in smoke so powerful it is choking people hundreds of miles away. Nature has reasserted itself.  "It's an event I could never have fathomed. The fire hasn't behaved like any fire we have seen before here," said Susan Skalski, a supervisor of the Stanislaus national forest service.  The inferno known as the Rim fire continued to rage on Wednesday for an eleventh day, and continued to grow, covering more than 288 sq miles and making it of the biggest fires in California's history.  It has obliterated much of the Sierra Nevada and parts of Yosemite national park, turning trees, vines, scrub and entire ecosystems into a smoking, lunar landscape.  It is difficult, as you navigate the embers and haze, to imagine anything ever growing in this desolation. Maps with place names such as Cherry Lake, Femmons Meadow and Pinecrest are obsolete. Scenes from Dante have replaced tourist idylls.  The rate of growth has slowed in recent days, and firefighters have contained 20%, evidence they are finally prevailing. Investigators have yet to determine what ignited the blaze. There is no mystery, however, over what propelled its breakneck growth.  "It's called fuel loading," said Parker Berrington, a firefighter, clutching an adze hoe amid crackling flames and groaning, collapsing tree branches, one tiny part of a vast battlefront. "This is an area we've been scared about for years."  Left unimpeded, nature used to produce periodic wildfires which purged undergrowth while sparing most trees. From the early 20th century, loggers objected – the cycle disrupted business – and authorities snuffed out blazes as quickly as possible. Thus undergrowth – fuel – accumulated. It was a time bomb.  "We're dealing with a hundred years of suppression," said Berrington, streaked and grimy from round-the-clock battle. "The most we can hope for here is to slow down the fire and secure the ridge line." Firefighting planes droned overhead, obscured by a grey shroud of smoke.  "Watch how the fuel load helps it climb that dry bark," said Johnny Miller, another firefighter, as fire licked up a pine. The flames ascended using "ladder fuels" – aka branches – and ignited the top, creating a crown fire that threatened to ripple across the canopy.  Climate change, drought and human settlement into previously uninhabited areas have played important roles in the growing number and ferocity of US wildfires but the Rim fire's speed – it leapt rivers and roads before firefighters could respond – owes much to the venerable piles of forest debris, and the hubris of denying fire.  Forest ecologists say it is no coincidence the Rim fire exploded through areas which had seen few or no blazes in almost a century – an unnatural absence since California's mountain flora evolved to burn.  The fire slowed as it moved into areas inside Yosemite national park that have experienced recent burns – control fires started by authorities, or natural fires, caused by lightning, allowed to run their course, reflecting growing recognition of nature's rhythm.  Flames can regenerate the forest. Some species of oak and pine rely on fire to reproduce. Deer and some other fauna thrive with the new growth which follows.  In many areas, the Rim fire's pent-up force annihilated everything, leaving a barren, scorched landscape firefighters refer to simply as "the black". Hollywood could scarcely conjure a bleaker vision of apocalypse.  Such images can be deceptive, however. "A lot of this fire is not as destructive as it looks. It's doing good," said Russell Mitchell, a firefighter captain, monitoring a blaze near a Yosemite park entrance. "It's killing some of the younger trees, but the older ones are surviving. As long as we can keep it out of the canopy it's good for the environment."  Mike Martin, a veteran firefighter and information officer, echoed the optimism. "There will be ecological benefits from this fire. We have learned over many years that not all fire is bad."  Only after it is extinguished will authorities learn how much of the blaze has been benign. For now the focus remains on its malign impact: 111 buildings destroyed, including 31 homes, air polluted as far away as Nevada, sequoias, electricity and water supplies menaced, communities evacuated.  Residents who gathered for a town hall-style meeting at the Sierra Bible church in Tuolumne county – site of the film High Noon and the TV series Little House on the Prairie – spoke of anguish. "I can't sleep or eat for the worry," said one woman. Her elderly, housebound mother would die if compelled to flee, she said.  Residents expressed gratitude to the 4,500 firefighters and support staff deployed to the area. They have been hailed as heroes; hugged and offered cookies. The Obama administration said the federal government would pick up most of the Rim fire fighting tab, currently at $20m.  The main base, a field of vehicles, trailers and tents high up the mountain, came under threat last weekend when winds drove flames to the perimeter.  On Wednesday the base hummed with generators and confidence. Maps showed black containment lines encroaching on red fire lines. Planes and helicopters flew sorties overhead.  "From a military perspective, this is a battle," said Jeff Smiley, a colonel with the California national guard who coordinated air support. Nature had struck a harsh blow but human resourcefulness would prevail. The fire would be extinguished. "Planning and execution, command and control … we have a system."  "This is my home turf. I grew up in Yosemite and did firefighting as a summer job to pay for college. I got a degree in business administration but realised I didn't want to be stuck behind a desk. So I kept on fighting fires. My business is the forest. This is my 13th fire season.  "The appeal is being outdoors. You're doing something different every day, clearing brush, riding in a helicopter, stuff at the station. We travel a lot. I've been on fire duty at pretty much all the western states. Fuel load is one of our biggest problems. Fires are getting bigger every year.  "I'm the captain and have a crew of 10. About half of us grew up together so there's a family atmosphere. During summer I spend more time with them than with my family. There is camaraderie and a sense of accomplishment.  "My wife works for the park as well so she gets it. I've got two little girls. The eldest is four and is beginning to understand the risks. She always asks when I'm coming home."
Rim fire continues to rage in the Sierra Nevada as fire crews come face-to-face with a timebomb 100 years in the making