One of my favorite cold weather activities is making, then watching, a fire in our soapstone fire view wood stove. The weather outside could just be cool or a raging blizzard, and the hearth fire gives the same sense of warmth and security that it did when humans first used fire. Our ancestors gathered fire produced by lightning almost two million years before learning to make it themselves. Paleontologists find ancient cave floors covered in charcoal with cooked bones and their ceilings sooted black. Beginning four hundred thousand years ago, fire-making tools began to emerge in these sites of human occupation. We still love to sit around a campfire telling stories as we cook food or just poke at the fire.
A carefully observed, intentionally built flame will reveal the living nature of fire as it consumes its food of fuel and oxygen. Heat and flame rise, of course, and it will hurt if touched. Fire burns in the space between fuel—too close will smother the flame while too far away will result in a weak and struggling fire. Fire loves good spacing of dry, warm fuel. Air arrives as needed to complete combustion. Tongues of flame dance a captivating performance in my wood stove and your campfire. Flickering between orange, yellow, and blue, the flame moves in tiny whirlwinds and bursts of light. A windy night bends the flames and sends sparks into the darkness to pit tiny holes in a nylon tent side. Campfires are mesmerizing and historically served humans with relatively little impact on the environment.
The same fire behavior is expressed on a massive scale in the megafires we are experiencing in the last thirty-plus years. These enormous fires are often referred to as “plume-dominated” fires where their behavior is defined by their own convection column. The rising intense heat of a big fire carries smoke, ash, embers, and fire brands high into the atmosphere. Spotter planes have been struck by burning branches at ten thousand feet. The swirling eddies of flame in my wood stove are now converted into hurricane-force winds in a big fire. The rising plume eventually cools in the upper atmosphere, then collapses under its own weight, cascading back to earth in a rush of unpredictable wind spreading the fire in new directions. The process creates its own lightning, wind, and rain of burning particulates called “fire weather”.
John Vaillant popularized the terms “fire weather” and “Petrocene Age” in his book entitled “Fire Weather”. He defines the Petrocene Age as the onset of the internal combustion engine and our total dependence on fossil fuels in manufacturing and daily living. A slightly different but related term for our current age is “Pyrocene Age,” coined by fire historian Stephen Pyne. He considers our current geological epoch as the dominant global influence of human-caused fire and combustion. He names two types of burning as “living landscapes” (forest fires, tundra, etc) and “lithic landscapes” (fossil fuels). His research leads him to suggest that our burnings are physically and chemically reshaping the earth’s ecosystems and atmosphere on the same enormous scale as the previous age of global glaciation.
This is new behavior for fire on Earth. It is promulgated by changing weather patterns creating huge swaths of dry fuel in a warming, dry, and windy atmosphere. The Petrocene Age of the last one hundred and fifty years has created these conditions. In 1860’s Paris, Etienne Lenoir patented the world’s first internal combustion engine. That technology revolutionized engines and the use of petroleum-based fuels worldwide. Millions of years of humans burning wood fires didn’t radically change their world. The same cannot be said for us living with the consequences of burning fossil fuels. I consider myself to be environmentally conscious, but I count twenty-four fossil fuel consuming individual cylinders in my vehicles, trail maintenance equipment, and backup generators. Every one of those cylinders contributes to greenhouse gases that contribute to the severely altered behavior of global weather and forest fires. Ironically, one of those engines drives my fire-suppression pump. In less than two hundred years of burning fossil fuels, we have changed the nature of Earth’s atmosphere, oceans, forests, glaciers, and animals.
There is an additional human activity contributing to these enormous and destructive fires. WUI is short for “wildland-urban interface”. The national standard of a WUI is defined as an area having at least 6.17 structures per square kilometer. This geographic edge zone occurs in northern Minnesota and around the world as growing populations convert wild, sparsely populated regions into urban development. These “wild” lands have been occupied historically by plants and animals with no need for fire and by indigenous populations using regenerating plant-based fuels. Periodic large fires in these natural places were caused by lightning and contributed to the overall health of forest ecologies. Modern urbanization is a different story. Human-caused fires outnumber lightning five to one. Once a fire starts, densely placed structures built with modern petroleum-based materials create a larger fire fuel load than the forests and grasslands destroyed to create urban development. Nobody who builds, sells, buys, or lives in a modern home thinks of the structure and surrounding amenities as a fire bomb. Consider vinyl siding and fencing as solidified gasoline. Petroleum-based tires will burn so intensely as to ignite the whole vehicle. Modern home furnishings made of petroleum-based materials burst into flames much faster than legacy furniture made of natural materials. Every garage and garden shed is filled with combustible and explosive products in common home use. Vyto Babrauskas, a physicist in Seattle, has extensively studied modern house fire behavior. In addition to many articles, his seminal thousand-page “Ignition Handbook” and “Fire Behavior of Upholstered Furniture and Mattresses” are used by urban fire departments to develop training and firefighting tactics. Even with this knowledge, modern housing is rarely included in the “fuel load models” that drive preemptive fire planning. Many fire departments have not prepared for WUI developments that increase the possibility of entire communities being destroyed. Developers and builders are not helping the problem when they build densely packed structures with flammable materials and limited access for emergency vehicles, civilian evacuations, and water.
This is clearly a potential problem for all of us living in northern Minnesota. As citizens and residents, it would be a good idea to not turn away from this emerging reality and potential disaster. I recently read parts of the Cook County Emergency Department’s Fire Plan. An impressive and extensive document of seventy-eight pages put together by a wide range of professionals. It is, however, almost ten years old, making several key elements out of date. I would suggest that the residents of each county read their fire preparedness plan and see how it relates to them personally and to the community they live in. Also, tap into your county’s Firewise resources. The state and federal governments are sources for Firewise information as well. These agencies see the need to be proactive in our changing world. Each resident can help by being informed, following the suggestions of fire professionals for our own properties, and then engaging our community in ways promoting safety for all.
