Are You Aware? Wildfires - Voices of MWEG

This is part IV in our “Concerning Climate” Awareness Wednesday series. Read the other posts in the series here.

Wildfires have been a part of the American landscape for centuries. Fire is a part of nature. Grasslands have historically burned every 15 to 30 years, and many forests have burned every 60 to 150 years. Burning is known to maintain forage and open woodlands, creating important wildlife habitats. Plants, such as the ponderosa pine tree with its thick bark, can survive low-intensity fires, and the seeds germinate in the fertile, recently burned soil.

Thousands of acres have burned every year, often with few consequences but occasionally with tragic outcomes. During the hot dry summer of 1910, wildfires killed 86 people and burned more than 3,000,000 acres in Northern Idaho and Montana. As a result, the U.S. Forest Service initiated an active fire suppression program in an effort to reduce loss of communities, life, timber, and other forest products. The program, aided by the surplus of aircraft following World War II, was generally successful through the 50s, 60s, and 70s — a period with a relatively cool, moist climate.

By the 1970s, it was recognized that lack of fire was leading to changes in plant communities — including heavy fuel accumulations and broader expanses of older-aged forests. The devastating 1988 Yellowstone fires were an example of the consequences. More recently, warmer, drier climates have further accelerated fuel accumulations. Add in the expansion of human developments adjacent to forests, and you have a perfect storm brewing. Verisk Analytics estimates there are 4.5 million homes at high or very high risk from wildfire.

Nearly every year, wildfires are changing our landscapes on a large scale and pose a bigger threat to people than they did a few decades ago. The Camp Fire in November 2018 destroyed the town of Paradise, California, and surrounding communities. Eighty-six people died, tens of thousands were displaced, and more than 18,000 buildings were burned. In October 2020, the Beachie Creek Fire in Oregon spread from 500 acres to more than 159,000 acres in one night as a result of a wind storm with wind gusts over 50 mph. So what is behind this shift from a quiet occurrence on the landscape to a wake-up call to so many? There are many factors at play.

Wildfire Ignitions

The number of wildfires varies widely each year, but the average has remained relatively stable over the past several decades. Although we experience roughly the same number of fires, they are larger, burn longer, and are more catastrophic.

Wildfires have a variety of causes. Lightning, for example, is a natural source of ignitions and one that historically has been an important process on the landscape. Unfortunately, human activities cause more than 80 percent of wildfires, and many of the large wildfires are human caused. Most are accidental, caused by things such as campfires, cigarettes, sparks from trains, power line transformers, target shooting, and even baby gender reveal parties. Sadly, a few have been started as purposeful arson.

Fire Behavior

Once there is an ignition, there are three key factors that drive fires: topography, fuels, and weather/climate.

Topography affects the speed of fire movement. Fire can burn on any landscape, but it will move fastest on steep slopes, burning primarily uphill.

Fuels feed wildfires. The amount, size, moisture level, and arrangement of trees, shrubs, grasses, leaf, and needle litter, and duff on the soil surface influence fire spread and intensity. Dry grasses will ignite quickly, and a fire can spread rapidly, but grass fires don’t produce much heat and can usually be extinguished quickly. Dry forests take a little more energy to ignite, but once fire gets a foothold, it can burn hot and, with sufficient wind, spread rapidly along the surface and also by spotting embers ahead of the main fire — sometimes a quarter- to a half-mile ahead. It can be very resistant to control efforts, often requiring a significant amount of rain or snow to stop its progression.

Weather and climate are key determinants of fire movement. Warm temperatures, low relative humidity, and strong winds create “red flag” conditions and serve as a warning that very active fire behavior can be expected. These conditions can be exacerbated by the cumulative effects of climate over a series of years. When areas experience short- or long-term drought, the vegetation becomes stressed and more readily receptive to fire embers. Stressed foliage will actively burn at lower temperatures, higher relative humidity, and with less wind. While tree needles or leaves may be green, they are much drier now than under normal climate conditions. Young pine trees in the northern Rocky Mountains were considered a fuel break — an area where fire is unlikely to burn through or burn very slowly — in the 1980s, but in recent years, fires have moved through them quickly. Additionally, shifts in climate have increased the length of wildfire seasons across the country. Higher temperatures and drier conditions occur earlier in the year and extend longer into the fall, adding weeks or even months to a fire season. Some areas now experience wildfires all year round.

Costs of Wildfire

Wildfires are tragic and costly. The National Institute of Standards and Technology estimates the annualized economic burden from wildfire to be between $71.1 billion to $347.8 billion (2016 U.S.). Annualized costs are estimated to range from $7.6 billion to $62.8 billion. Annualized losses are estimated to range from $63.5 billion to $285.0 billion. (In comparison, the cost of the Supplemental Nutrition Assistance Program, or SNAP, was $79.2 billion). Besides the direct loss of civilian and firefighter lives, Stanford University estimates that 3,000 deaths in California in 2020 were a result of wildfire smoke.

Other costs of devastating wildfires include displacement of individuals and families during and after a wildfire, post-traumatic stress disorder, homelessness, lost income and/or jobs, lost economic benefits from tourism or logging, and decreased water quality, to name a few. Such impacts can have greater effects on those with lower incomes with fewer resources with which to recover.

Making Changes

Of the three drivers, fuels are the quickest and easiest to change and thus, typically, the focus of land managers’ efforts to reduce wildfire impacts. The U.S. Forest Service estimates that there are more than 105 million acres managed by federal agencies that are at high or very high risk of experiencing catastrophic wildfire. State and federal agencies actively work to reduce the risk, with a focus on fire prevention and reducing fuels. Federal budgets for “hazardous fuel reduction” have steadily increased during the past two decades.

Individuals and communities can play a key role in reducing the threat of and impacts from wildfire. Here are a few recommendations:

Understand the risk of wildfire in your community.
Know what is in your community wildfire protection plan or encourage development of a plan. (Read more here on how to create a community wildfire protection plan.)
Assess your property for wildfire risk and preparedness (Read more here on preparing homes for wildfire.)
Prepare for a potential wildfire evacuation. (Read more here on how to prepare for a wildfire.)
Know the causes of human ignitions in your area and work to prevent them.
Encourage your congressional delegation to support legislation and funding to reduce wildfires and address climate change.
Take actions recommended in previous Awareness Wednesday posts to reduce your impact on climate change.

Climate models predict a 30 to 600 percent increase in the extent of wildfire through the 21st century. As the climate continues to warm and extreme events increase, it will be much harder and more costly to affect changes in fuels to significantly modify the current wildfire trajectory. While changes to climate occur over a much longer period, if no efforts are initiated to moderate increasing temperatures and other impacts, it may become impossible to change fuels sufficiently, and we will need to adapt to large, impactful wildfires as a “new norm” — if we can.

Other resources: Future Wildfires and Flooding: Estimates of Increased Likelihood across the United States | Environmental Health Perspectives | Vol. 126, No. 12 (nih.gov); Wildfires and Climate Change | Center for Climate and Energy Solutions (c2es.org); Climate Change Indicators: Wildfires | US EPA; Wildfires | Climate Signals

Source: EPA, National Interagency Fire Center