It’s been a season on the precipice for the country’s 400 smoke jumpers, the aerial daredevils who fly into remote fires and use hand tools, dirt and guts to bury flames. So far this year, more than 79,000 fires have burned 3.5 million acres nationwide, more than double the annual average. Smoke jumpers specialize in attacking small fires fast and hard, before they turn into ones like the Jamestown, Calif., blaze that destroyed 7,000 acres last week – along with the set of the movie ““Back to the Future III.’’ It’s an increasingly difficult task. With so many fires in western Montana, the base in Missoula ran out of jumpers at least once this month. But even as the job edges from dangerous toward impossible, the smoke jumpers keep jumping. ““Your fate is unknown: Is it going to be a tough jump? Is it a difficult fire?’’ says Cameron Lawrence, a jumper for six years. ““That uncertainty gives you a hell of a respect for what we do.''

It’s hard to say which is more perilous: getting to the fire or putting it out. Jump- ers carry 100 pounds of gear on each mission, which makes getting from the unsteady door of a low-flying DC-3, through the treetops and down to the forest floor extremely treacherous. Putting out even small fires can take days, but flames aren’t the only danger. Mike (Gizmo) Waldron, one of the Missoula jumpers, had to face down a cougar in California. In Arizona, lightning struck a nearby tree and sent an electric jolt through his feet and out his tongue. ““It felt like an M-80 went off in my mouth,’’ he says. But he was lucky. Since 1940, 22 smoke jumpers have died on the job, including three of the 14 firefighters who perished on Colorado’s Storm King Mountain in 1994.

Yet some fire experts argue that smoke jumpers have done their job too well. They say the jumpers have robbed the West of the healthy, slow-burning blazes that remove tinder from the forest floor. Some U.S. Forest Service officials want smoke jumpers to spend more time managing controlled fires that will make the forests safer in the long run. It’s a controversial proposal, but many smoke jumpers support it. ““The future of the smoke jumper may be in their ability to use fires when they can’t fight fires,’’ says Jerry Williams, a Forest Service official and former jumper. ““There will always be a need for smoke jumpers.’’ Especially with another month left in the fire season.