by Chuck Dayton
September 20, 2011
This fire started by lighting about 4 miles south of our summer cabin and burned uneventfully and locally for about 2 weeks before it started to grow. The weather stayed very dry and when the winds picked up, neither of which was predicted, the fire took off. It doubled each day for about 3 days till it became about 11 thousand acres. Then on September 12, it took off and burned about 60,000 acres or more in a single day. Fortunately, the winds blew away from us most of the time, although we did have some days with a lot of smoke.
This was a rare phenomenon. The computer models predicted a .02 percent chance of this fire getting to a size of about 10,000 acres: 2 chances in a thousand. What happened was a perfect firestorm, where extremely dry conditions coincided with fierce winds, 25 knots gusting to 40. This produced a pyrocumulonimbus cloud (see photos) driving burning ash skyward in a kind of a fire soup, which rained fire downwind. It was visible from satellite, and smoke was present hundreds of miles away. Several campers and a fire crew got caught in Insula and north of Kawisiwishi lakes, and reported 3 foot waves, zero visibility and air full of burning ashes. They barely survived.
Several of us who understand the rationale of the “let burn” policy were pretty worried about some kind of angry outbreaks at the Ely informational meeting on September 13th. There were none, although I understand there was some of that at the meeting in Isabella, in the path of the fire. The Forest Service did a great job of explaining the fire, the decision to let burn and the efforts to control it that are now underway. We’ve come a long way in 40 years.
Second, Myron “Bud” Heinselman, my beloved mentor and expert witness on the Boreal forest, whose work in mapping the fire history of this ecosystem demonstrated the need to let natural fires burn when that can be done safely, wrote in his book, The Boundary Waters Wilderness Ecosystem, that Climate Change will increase the probability of very large fires that cannot be controlled
Heinselman was prescient on this subject. He wrote almost 20 years ago, before the big blow down of 1999, that “If Greenhouse Warming occurs as predicted, and if precipitation increases very little of even decreases in summer as many models project, major changes are foreseen in fire regimes.” Less moisture will be present in the late summer, as droughts become more protracted and severe, drying out all soils and wilting vegetation. Second, drought will cause the death of lots of trees, which will produce more fuel. Heinselman also notes that climate change causes related effects including “higher incidence of strong windstorms”, making the area more vulnerable to blow downs. Moreover, the increased spread of insects and tree disease may find optimal conditions in the old forests where we have long suppressed fires. He concludes: “vast forest fires on scales not seen even before European settlement may be the primary agents of death for the Boreal conifers instead of gradual tree by tree or selective stand mortality due to drought or increased insect or diseases losses triggered by climatic change. The BWCAW may see a succession of years like 1988 in Yellowstone. The difference may be that climatic change, not normal drought recurrence, will be the reason.”
This really is a big fire. Heinselman notes, based on his historical mapping of the age of the forest mosaic (using a boring tool to extract a core and then counting the rings) that the 64 percent of the BWCAW area, which burned between 1727 and 1910, was generated by just 8 large fires, each exceeding 100 square miles. This one is over 150 square miles.
Bud notes that NOT letting fires burn in the wilderness carries just as big a risk as letting fires burn. Fire suppression leads to fuel buildup that carries the risk of runaway fires. This fire is bounded on the west by the Turtle lake fire of several years ago, and the USFS is not worried about a spread in that direction. Of course one of the reasons this fire could take off was the absence of fires for so long, due to fire supression. One benefit of the fire will be the renewal of a vast area and less fire dangers there in years to come. Also, morel mushrooms and blueberries will explode for those willing to get there by paddling. I do shudder to think of the loss of wildlife in that rare firestorm, but future habitat will be great there.
Bud also discusses the role of fire in forest renewal throughout the book, and that’s a point which most of the the news media seem to be missing although there have been a couple of stories about the benefits of fire. “Running Crown fires were undoubtedly the natural agents that produced the vast stands of jack pine, black spruce, aspen and paper birch that cover much of the BWCAW’s virgin forests north and south of the echo trail, and from Hudson, Insula Alice, Wine and Cherokee lakes north to Knife, Cypress and Saganaga and the Gunflint trail.” Of course since Bud wrote this, some of that was blown down, including large areas north of Insula and Alice.
Obviously, a let burn fire policy needs to be grounded in the protection of life and property. The irony is that every time we put out a fire, the next one probably will be worse. Also, as climate change increases, the risk of very large and uncontrollable fires increases, as Bud wisely wrote. So in addition to stopping climate change (may that turn around in our lifetimes), a let burn policy under carefully controlled conditions needs to continue. I’m assuming it will.