Resilient Cities and the Increasing Risk of Suburban Wildfires
The impacts of wildfires do not stop at property boundaries, and a silver bullet does not exist to eliminate risk. Pre-fire risk reduction, on a variety of fronts, can help communities be more resilient.
Published on:
February 24, 2022
Disasters and emergencies can affect anyone at any time quickly and without warning. It can force you to evacuate your neighborhood or confine you to your home. Basic services such as water, gas, electricity, or telephone may not be available for a long time. You need to be prepared to be self-sustaining, especially in the first few hours after an emergency, or more than that—you need to be resilient.
The concept of resilient cities and communities goes back to urban socio-environmental systems that seek to consider the contexts of uncertainty. They teach us that we must be flexible and capitalize on opportunities. That is, we benefit from demonstrating flexibility to live with the unexpected and adapt.
Although disasters and emergencies can happen anywhere, in some places, natural phenomena become even more recurrent each year. In South America, for example and according to MapBiomas, an area larger than England catches fire in Brazil annually. In total, over the last 36 years, 61,700 square miles have been engulfed by fire. The cumulative amount of land burned during this time is enormous—equivalent to 19.6% of Brazil.
Wildfires in North America have set records in recent years. For example, in the United States, Colorado experienced the most destructive fire in its history in December 2021, stretching over 9.4 square miles (24 square kilometers). According to PBS, in 2020, Colorado suffered three of its biggest fires so far on record, while a prolonged drought dominated the western U.S. In 2013, another fire destroyed 489 homes outside of Colorado Springs and killed two people.
Severe fires have become more frequent in the western U.S. in recent decades, with hotter and drier seasons. The Front Range of Colorado, where most of the state's population lives, had an extremely dry and mild autumn this past season, and the winter thus far has remained almost dry. The Denver-Boulder area remained dry and Denver set a record for consecutive days without snow before a small storm in December 2021. The fire season—which used to last roughly from May to November—has been getting longer and longer.
Climate change, unsurprisingly, is behind the increase in extreme weather swings. The Colorado wildfires are a catastrophic symptom of drought in the United States and illustrate some of the impacts caused by global warming. The Colorado River, which supplies water for some 25 million people, faced an unprecedented water shortage in 2021 (USBR, 2021). An official shortage was declared for the first time at Lake Mead, the largest reservoir in the United States. In August 2021, shortly after water levels in the reservoir dropped to an all-time low in June at the Hoover Dam, at the southern end of the lake Water cuts were made in Arizona, Nevada, and New Mexico in early 2022, as well as in California, as the drought affected available hydroelectricity in the state, putting even more strain on a power grid struggling to keep the lights on. According to Assistant Secretary of Water and Science Tanya Trujillo, in an interview with the USBR, the Colorado River is facing unprecedented and accelerating challenges.
Cities are like living organisms that are constantly changing. According to Minor, Penney, and Kim of CPR News and data released by the U.S. Census Bureau (2021), Colorado's population grew by almost 15 percent between 2010 and 2020. This represents an increase in Colorado's population from 5 million in 2010 to about 5,750,000 this year. Most of the population growth, evidenced by a decade of rising traffic and house prices, has occurred along the Front Range.
In the last 10 years, “Denver County added 115,364 new residents. El Paso County, home to Colorado Springs, totaled 108,132, the data show. The fastest rate of population growth was recorded in smaller Front Range counties, including Broomfield, which grew by 32.6%; Weld at 30.1 percent and Douglas at 25.4 percent.”
Cities keep growing. Currently, there are stretches between Denver and Fort Collins that were previously uninhabited, but now it's like a long stretch of continuous development. However, these houses are built with flammable materials, such as wooden siding and an asphalt roof. While the cause of the recent fire is still under investigation, experts say it's clear what allowed it to spread so quickly. According to Jennifer Balch, a fire scientist at the University of Colorado Boulder, in an interview with the Chicago Sun Times, three ingredients were needed to start this fire: fuels, a hot climate, and an ignition source. Colorado is a dry landscape full of flammable material for most of the year, like the houses themselves that are a part of a flammable system that burns easily and contributes to further spreading the fire. According to Balch, “the lesson learned throughout this event in Boulder Country is that the “wild-urban interface is much bigger than we thought.”
Experts told the Chicago Sun Times that similar wildfires will become more common as climate change warms the planet and suburbs grow in fire-prone areas. The Colorado fire forced 35,000 people from their homes, burning two densely populated suburbs between Denver and Boulder. This means that a wider area is under threat from wildfires. That frontier area—where structures built by people meet wild underdeveloped areas—is prone to wildfire. As more people move to areas where wildfires occur, the threat increases. According to Overpeck in this same interview, he said, "We're building towns and cities and infrastructure, so it's only a matter of time before we have entire cities burning like we had in California and events like this one in Colorado."
Disaster Safety states that choosing the right fire-resistant plants and building materials can help to reduce wildfire risk. One of the best protection recommendations is to keep the area outside the house clear of all combustible materials. The use of noncombustible hardscapes is beneficial, such as concrete pavers, flagstone paths, decorative gravel (rock mulch), and natural stones. Finally, the best option is to keep the area clear of plants, especially if you have combustible sidings such as wood or vinyl.
Another important insight about wildfires is that the imminent dangers of fires can remain hidden even after the fire has ceased. Air pollution scientist Joost de Gouw, at the University of Colorado Boulder, has discovered this in his ongoing research. He shared several profound insights during the Converge Virtual Forum in January 2022. We learned that the impacts on air quality did not stop after the recent Boulder County fire. In addition to prolonged smoke in the air, he stated that many people did not return home because they were worried about their health, as their homes smelled of smoke and ash accumulation was widespread. Residents were also concerned about respiratory health impacts when cleaning up windblown ash that may contain substances like metallic asbestos.
The impacts of wildfires do not stop at property boundaries, and a silver bullet does not exist to eliminate risk. On the other hand, pre-fire risk reduction, on a variety of fronts, can help communities be more resilient. That means becoming adaptive to wildfire, so they can live with wildfire without harm and without extensive wildfire suppression efforts. According to Forest Service U.S. Department of Agriculture, fire adaptation happens when local multi-jurisdictional stakeholders and everyone who lives and works in the community work together to identify risk, mitigate it, and maintain the work over time.
The cities of the future must be resilient and have supportive management capable of reducing risks and responding effectively to the occurrence of a natural disaster. Cities are made of people and for people, so this means that resilience must be perceived in both spheres: people and structure. Resilient people are more flexible during disasters and are able to recover quickly from the impacts caused by these events. Disaster resilience is based on individuals' decisions to share their responsibilities for disaster prevention, response, and recovery.
As disasters also cause a high social and economic cost to societies, it is necessary to build resilient structures. Resilient structures are less susceptible to ignition from embers, the primary cause of structure loss. A resilient structure, for instance, is constructed of less flammable materials, has a class “A” roof (not a cedar shake roof or siding), has metal screen over eave vents, and under decks.
It must be understood that resilience must not just be created after the disaster to situate the problem, but earlier. The disaster demonstrated that there are problems that must be recognized—such as the way we build our homes—to build a culture of safety and resilience at all levels; reduce underlying risks and strengthen disaster preparedness for effective response and recovery at all levels.
REFERENCES
Bureau of Reclamation – USBR (2021). Reclamation announces 2022 operating conditions for Lake Powell and Lake Mead
Disaster Safety (2021). Fire-resistant landscaping for your home.
Forest Service U.S. Department of Agriculture (n.d). Fire Adapted Communities.
GONÇALVES, C (2017). Resilient regions, cities and communities: new development principles. Brazilian Journal of Urban Management. (v.9., pp. 371–385).
MapBiomas (2021). Each year, Brazil burns an area larger than England.
PBS Org. (2022). Colorado wildfire caused $513 million in damage.
