Friday night, Sept. 1, he nursed his swollen, blistered feet and dragged his aching bones to bed for a well-deserved 10-hour nap.
Crickets chirping outside his window sounded almost foreign after he'd grown accustomed to the constant background roar of the insatiable flames.
For awhile that weekend, Mensen found himself instinctively glancing upward to warn his crew of falling timber.
As a three-year veteran of the U.S. Forest Service, fighting forest fires isn't new to Mensen. He'd been called to fight blazes throughout the Rocky Mountains, and this is his third year as a certified smoke chaser.
But the magnitude of the blaze consuming Flathead National Forest makes his previous battles look like pesky bonfires gone awry.
"Overall it was an awesome experience," Mensen said of the Montana blaze. "Quite a bit happened in those two weeks."
While there, he saw some of the most horrific fires he'd ever seen, while at the same time catching breathtaking glimpses of Mother Nature's most scenic landscapes.
All in a day's work
Fighting forest fires is seasonal work for Mensen, whose regular job with the Forest Service is patrolling the Minnesota Boundary Waters in Superior National Forest.
As a trained smoke chaser, he's often called to out-of-state assignments to fight fires in late summer. This time the call for help came from Flathead National Forest in western Montana where fires have been burning since early July in an area that hasn't seen rain all summer long.
Mensen flew out Thursday, Aug. 17, and returned home Friday, Sept. 1. During his 14 days of work on the job he logged almost 200 hours of fire fighting and racked up a sizable paycheck.
"The money's good and it's pretty exciting work," Mensen said when asked why he got involved in forest fires.
Mensen was in charge of a 10-person Minnesota crew. As a crew leader, he said one of the most important parts of his job was to keep everyone motivated.
"It's hard to get up in the morning," he said. "When you're putting in 12- to 18-hour days you get pretty drained."
The primary job of a smoke-chaser is to squelch spot fires that flare up from burning embers carried by the wind - sometimes as far as a quarter mile.
It involves backbreaking labor from 4 or 5 a.m. to 10 or 11 p.m. "We'd burn 4,000 calories a day, no problem," Mensen said.
"At the end of the day, it's probably your feet that hurt the worst. You get blisters from hiking around the steep slopes and rough terrain. It's probably a 60- to 70-degree grade."
Hand tools and human strength
Armed with nearly 70 pounds of survival gear and fire fighting equipment, smoke chasers serve as an initial attack, battling flames by clearing burnable foliage.
Much of their work is done with a specialized hand tool called a pulasky. The combination of an ax and a hoe is used to clear brush and hand-dig a line of dirt to serve as a fire break.
Often roads and rivers are used as natural breaks, and bulldozers clear ground on either side to prevent the flames from jumping.
But in mountainous terrain, the only line of defense is a hand tool and human strength.
In addition to the pulasky, the standard gear pack includes a chainsaw, headlamp, fuel, water and lunch - often food comparable to Army rations.
Always heads up
A critical piece of equipment in every gear pack is a silver emergency fire shelter. If used properly, the small fire-proof tent is designed to protect a firefighter trapped in a blaze.
"You always make sure you have your fire shelter, but you never want to get in that position," Mensen said. "I never felt I was in that position, but it was always a heads-up situation."
He explained that while working on a fire on Cyclone Ridge, a burning tree fell and split his crew in half.
As a crew leader in charge of rookie firefighters, Mensen said a big part of his job involved constantly being on the lookout for falling timber and rear spot fires that could close off planned escape routes.
He said he enjoyed working on the spot fires - apart from firefighters battling the main fire. "The bigger fires get kinda crazy," he said. "With the smaller fires, at least you know who you're working with.
Despite his long hours and hard work, Mensen keeps his labor in perspective by observing people who do it full-time.
"Some of the people I worked with in Montana get two days off every month, and they've been working for two months," he said. "It's a totally different world for these guys. It's hard to explain. It's almost like a weird subculture."
Priceless rewards
Though his blisters are still healing, Mensen said he's ready to go back and do it again, because the work has priceless rewards.
For example, in between battles with spot fires, he and his crew would have brief opportunities to enjoy nature at campgrounds several miles from the fire.
"It's the first time I'd been in Montana, and it's just such beautiful country," Mensen said. "The mountains and lakes are just gorgeous. - The scenery's just something else."
In addition to the striking mountain peaks emerging from an endless sea of pine trees, Mensen also described a rare opportunity to cast his line in a scenic fly fishing hole.
He said the best rewards came in the form of thanks from local residents.
"When we'd go into town at night to eat, people would see us and smell the smoke and they'd know we were fighters. They'd come up to us and say thanks. It's pretty amazing," he said.
"It's just a pretty good feeling to get that kind of pat on the back."
Mensen said it's that kind of response that will keep him interested in fighting forest fires.
"It's definitely rewarding," he said. "You feel you're doing something good. You're saving lives and protecting resources. I can see myself doing this for years to come."