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What will the Minnesota fire season bring?

We have only about six weeks or so until wildfire season starts in northern Minnesota; if the experience of the last two years — the two worst fires in the region since the 1800s — are a prelude, there could be some big blazes this spring and summer.

With that thought in the back of my mind, I participated in a wildfire symposium sponsored by the Joint Fire Science Program, U.S. Forest Service, National Interagency Fire Center and the American Society of Environmental History in Boise, Idaho, last week.

Also on hand were Jack Cohen, one of the country’s foremost fire scientists, and Steve Pyne, who has written more about fire history and historic fires than anyone.

These two guys — both began as firefighters — have been in the fire business long enough not to varnish their opinions. For example, Cohen noted that in 2003-2004, the government spent $587 million on fire suppression to protect structures, “which was more than the structures were worth.” The logic of that approach was not left hanging.

Cohen works out of Missoula, Mont., at the USFS Fire Sciences lab. He helped write an extensive report after the 1999 blowdown in the Boundary Waters Canoe Area Wilderness for the U.S. Forest Service.

Much of Cohen’s work is on “home ignitability.” Fire management has focused on controlling the blaze, rather than the compatibility of the structures to fire, he said. Fire-resistant building materials are one example of compatibility.

Cohen and Pyne, who is a professor at Arizona State, agree on the danger of cedar roofing shingles, which are now relatively uncommon in Minnesota but still in regular use in the West.

“We know convincingly that combustible roofing is lethal,” Pyne said dryly. “We’ve known that for approximately 10,000 years.”

One factor that stands out in wildland-urban-interface fire research is how often a home is set ablaze not by wooden shingles but by a stray broom under the deck, dry pine needles in the gutter, or plastic patio furniture cushions catching fire. “A home commonly burns after the main fire has passed by,” Cohen said.

Cohen promotes a prevention idea called the “home ignition zone.” He wants homeowners who live in wildfire-prone areas to carefully tend a 100-foot circle around their dwellings. This does not mean stripping all the vegetation down to the dirt and raking it like a baseball infield. But spaces in the coniferous canopy near a building will slow or divert a crown fire; brush, grasses, dead juniper, cedar and other dry vegetation should be kept away from a structure. “Rake the needles off the deck and from around the house,” he said.

And he hates balsam fir, America’s favorite Christmas tree but one that “burns like mad.” There’s a lot of balsam fir in northern Minnesota, he said, much of it planted by cabin owners too close to their dwellings. Aspen and birch have more fire resistance.

A sprinkler system often works, he said, but someone needs to be there to turn it on.

Which brought us to the issue of mandatory evacuation. Cohen and Pyne have strong feelings about that, too. “I can defend my house with a bazooka and an M-16, but not a garden hose and a rake?” Pyne asked.

One idea, now being tested in Australia, is called fighting the fire from the inside out. Assuming the house and the surrounding land are appropriately fire-resistant, a person rides out the intense period of the fire inside the home and then jumps outside to the hose and shovel to extinguish any burning embers that are left after the main fire has passed. “It’s only going to work if you have reduced the vulnerability of the house,” Cohen said.

One is tempted to say “don’t try this at home.”

Local law enforcement officials are commonly called on to evacuate a fire zone, and sometimes the evacuation is more dangerous than the fire, Pyne said.

Sometimes the expectations placed on firefighters are unreasonable. Bill Summers, now at George Mason University and a longtime federal fire official, put it this way: “The public has urban values living largely in wildland settings.” Cohen pointed out that a five-minute response time to an emergency call “when you are 10 miles up One-Road Canyon” is not possible.

Last May, the Ham Lake fire, near the Gunflint Trail, burned about 120 square miles in the United States and Canada over 14 days; there were no deaths and 11 injuries. About 140 structures burned, including 10 year-round homes.

In 2006, the Cavity Lake fire, also off the Gunflint, burned about 48 square miles, all on the U.S. side and all in the BWCA. Two firefighters were hurt. The cost of fighting the two fires was in the neighborhood of $20 million.

Ham Lake and Cavity Lake were the two largest BWCA fires ever, and the largest in the region since fire suppression became government policy in the 20th century. The Ham Lake fire was apparently started by a camper; Cavity Lake’s fire ignited by lightning.

In both cases crews were on the scene within several hours. Our current fire-protection system is based on real-time intervention, Cohen said, and fire protection resources are often overwhelmed. “Things are changing,” he added. “What is the appropriate response? What is the analysis of that response?” 

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