Environmental and financial strains paired with demographic changes have made that strategy ineffective in an era of record-size fires sweeping across the West, experts say.

"We can't do things like we did in the 1970s and 1980s," said George Weldon, deputy director of fire, aviation and air for a regional Forest Service office in Montana. "The fire environment in a lot of situations is exceeding our capabilities to control large fires that burn the entire summer."

Climate models show a warming West where snowmelt from the mountains occurs earlier and dry conditions persist longer, setting the stage for blazes that reset measures for scale and intensity.

In 2006, the Scripps Institution of Oceanography released what scientists consider the definitive study on the link between global warming and worsening western wildfires, the same year the nation registered an all-time high of 9.8 million acres burned and the deaths of 24 wilderness fire-fighters.

Today, 43 percent of the Forest Service budget - $4.5 billion for this fiscal year - is funnelled to its fire program, up from 18 percent in 2000.

That means the agency has less money for everything from recreation to range management, even as fire bosses become more selective about the blazes they will fight.

FIRE-DEPENDENT ECOSYSTEMS

Heightening the challenge facing fire crews is the increased push of housing into natural, fire-dependent ecosystems that once would have been allowed to burn.

Last summer, blazes that broke out in the West accounted for more than 7 million acres of the 9.3 million US acres burned by wildfires, according to data from the National Interagency Fire Centre.

Idaho led states for burned areas at nearly 2 million acres, followed by California at more than 1 million acres and Nevada at about 900,000 acres.

Fires in those three states killed at least a dozen people, forced the evacuations of hundreds of thousands, cost more than $1 billion to fight and tallied an untold amount in damages.

In Idaho, smoke billowed for weeks into a host of communities from surrounding wilderness-based blazes that fire managers determined did not pose the imminent threat of wildfires raging near the upscale resort community of Sun Valley, where the bulk of crews and equipment was sent.

The tactics used in that state, where lives and property trumped natural resource values, show the shift among fire bosses in evaluating which blazes to fight.

"We need to look at how we do business," said Weldon. "It's not driven by costs so much as determining whether certain actions are going to be effective."

Weather prediction will play a key role, experts said, prompting decisions about the timing and scope of fire-suppression efforts.

With the National Oceanic Atmospheric Administration Climate Prediction Centre pointing to higher than usual temperatures this summer for the West and lower than average rainfall, fire bosses must "be more proactive on how to deploy fire fighting resources," said Rick Ochoa, fire weather program manager for the National Interagency Fire Centre.

In the face of mounting wildfire risks, federal, state and local governments are seeking to place at least some of the onus on homeowners themselves.

"Where we live and work now is going to require us to have survivable structures and survivable communities," said Weldon. "People will have to decide if where their houses are, what types of materials the houses are made of and whether clearing around the houses will make them survivable when wildfire occurs."