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Markkula Center for Applied Ethics

Wildfires: Identifying Vulnerability in California

Rim Fire

Rim Fire

Efren Oxlaj

The Rim fire burning near Yosemite, 2013 (image from USDA).

Efren Oxlaj was an Environmental Ethics Fellow at the Markkula Center for Applied Ethics during the 2018-19 school year. 

This article uses the Framework for Ethical Decision Making by Markkula Center for Applied Ethics.

Recognizing an ethical issue & getting the facts


Recently, I went on a hike at China Camp State Park. It’s a hidden gem bordering the greater San Pablo Bay and if one is lucky, deer and turkeys can be spotted in their natural habitat. Although the southern part of the park is characterized by rolling hills and the abandoned Chinese fisheries, the Northern half is dotted with human settlements. It is not surprising that people like to live near or in the middle of undeveloped land: we often associate nature with tranquility, cleaner air, and pleasing aesthetics in the forms of landscapes or views. These are often the reasons why people, including myself, choose to go on hikes in wilderness areas.

Unfortunately living near nature comes with the risk of wildfires. For instance, according to CAL FIRE, the top 20 wildfires in the state have killed 302 people since 1932[1]. The most recent devastating wildfire, the Camp Fire, killed 85 people last year in the town of Paradise [1]. Although it may seem that California suffers the most, the spike in wildfires appears to be a global phenomenon. To illustrate, Sweden experienced 11 wildfires in 2018 with some of these wildfires burning in the Arctic Circle [2]. Similarly, Greenland saw an unusually prolonged wildfire in 2017 despite having 80% of its land area covered in ice [3]. Given that climate change is expected to increase global temperatures, the risk of more wildfires both in California and throughout the world is concerning. Therefore, identifying who lives in areas especially prone to wildfires can help us prepare better and save lives.

To understand the ethical implications of potential solutions, I will rely on the Framework for Ethical Decision Making developed by the Markkula Center for Applied Ethics.  This framework provides a series of guidelines for understanding an ethical issue and providing a solution. Each section will reflect the steps (in italics) found in the framework. These steps include: recognizing an ethical issue, getting the facts, evaluating alternative actions, making a decisions (and testing it), and reflecting on the outcome.

The Wild-Urban Interface

Researchers classify the intersection of human settlement and wilderness as the wild-urban interface (WUI). There are two types of WUI: interface and intermix.  Interface WUIs are characterized by settlements that are near undeveloped land [4]. On the other hand, intermix WUIs refers to communities with dispersed human settlements in undeveloped areas and wildlands [4]. The most recent data suggests that the WUI constitutes 10% of the contiguous United States and that it has grown rapidly between 1990 and 2010[5]. In fact, in 2010 researchers estimated that 25 million more people resided in the WUI than in 1990[5]. There is clearly a growing affinity for living next to nature. With this trend also come questions of ethics: Should we be building in the WUI? How should we prioritize vulnerable populations already living in the WUI?

Not surprisingly, there are no easy answers to these questions. People build in the WUI presumably because they like being surrounded by nature, or to avoid the more hectic and industrial lifestyles of cities. Yet in doing so, they place themselves at higher risk of property damage and even death. Banning construction in the WUI is probably both impractical and undesirable, but we should improve how such communities prepare for a wildfire. Communities can prepare by taking the preventive measures found in resources from agencies such as CAL FIRE and FEMA. Some communities also have community wildfire protection plans (CWPPs) which contain important information on local conditions and mitigation measures. Additionally, people often return to the place of their homes after a wildfire. A quick search on the internet reveals a considerable number of resources for what do after such an event. However, there appears to be a lack of suggestions for where to go when coming back is not an option. Taking proactive measures to mitigate the risk of a wildfire might, therefore, be the best course of action to protect the wellbeing of communities and avoid the high costs of reconstruction.

Vulnerability Index

In order to identify vulnerable populations, I set out to create a vulnerability index. The index considers median income, percent of people over the age of 65, percent of people living alone, and percent of people without a vehicle by census tracts. Income is important when considering vulnerability because it affects an individual’s ability to bounce back from hardships, especially economic losses (e.g. burned homes) [6]. For example, we expect more affluent residents to rebuild and recover faster than those with lower incomes. Similar to income, age can also increase or decrease vulnerability depending on whether individuals lie in the older or younger spectrum. Researchers have recognized that the elderly may be more vulnerable if they suffer from limited mobility [6].  This limitation may hinder an individual’s ability to cope during a catastrophic event such as a wildfire. Along these lines, living alone can increase vulnerability. There is evidence suggesting that self-neglect is common in old age and is correlated with living alone [7]. Individuals living alone may already be in need of social support and experiencing a wildfire would, presumably, exacerbate their ability to take care of themselves. Lastly, not having a vehicle can greatly reduce the ability of residents to escape to a safer area during a wildfire. Unfortunately, as the media has reported for previous fires, being trapped in a vehicle during a wildfire can also be deadly.

By taking the variables previously mentioned, I completed a simple vulnerability index for the state of California using Census data. The index provides a score which reflects the weighted quintiles for the selected variables. A more detailed explanation of methods can be found here. The score measures vulnerability for census tracts, with higher scores suggesting increased vulnerability to a wildfire. In other words, census tracts with higher scores reflect elevated percentage of people living alone, people over 65, incomes above the median, and percentage without a car. To enhance the utility of the index, I also rely on WUI data and fire hazard severity data—a measurement of wildfire prevalence.  Other researchers have also created similar yet more robust tools that can be used to measure vulnerability. For Santa Clara County alone, the index shows a prevailing score in the range of 0.80-1.10. These scores are above the average (0.75) for the entire state. Perhaps more concerning, there are a few census tracts with scores in the rage of 1.10-1.14. These census tracts are located near Alum Rock Park and west of Cupertino. Areas in Los Gatos and Saratoga are also in the same range. Using CAL data, it also appears that communities living near the Santa Cruz Mountains and the Diablo Range have a higher risk of a wildfire. This makes sense given that these communities are also found in the WUI and might be surrounded by grasslands and forests.  The areas with higher index scores are of particular concern and should be prioritized when considering wildfire management strategies.



Map: Image of the Index scores for Santa Clara County. To see the other layers presented and the full methodology, click here.

Evaluating alternative actions

Recommendations using the Ethical Framework

The ethical framework provides five sources of ethical standards to consider when laying out a solution. The utilitarian approach is the one that generally causes the most good. This might entail banning all housing in the WUI and relocating all individuals to a different location. In theory, this would save all lives since no one will be in the immediate path of a wildfire. Unfortunately, this is simply not practical, and could lower well-being by depriving people of their homes and access to nature. The next standard, the rights approach, is one that “best respect the moral rights of those affected” [8].  One possible solution under the rights approach would be to leave homeowners alone and let them decide how to best protect their homes, thus exercising their rights to freedom and property. A limitation of this approach would present itself in the form of unequal protection from wildfires by different homeowners. It only works if all property owners choose to protect their homes to avoid risking a neighbor’s home in case of a wildfire. Another approach would entail using the fairness or justice approach. This might entail providing government support those in the WUI that are financially unable to protect their homes, but not to wealthy homeowners, thereby fostering fairness.  Similarly, the just approach suggests priority should be placed on homes with elderly and young children, two groups potentially facing more obstacles during a wildfire. One limitation of the fairness approach is identifying the populations that need extra support or priority relative to the rest. Yet another solution could be one that follows the virtue approach. This approach asks the individual to make decisions “consistent with certain ideal virtues” [8].  However, this approach appears difficult because we would need to understand the virtues of a community to provide solutions that are consistent with their values. Individuals may place a higher value on prudence or protecting the natural beauty of the wildland.  For example, some might place a higher value on expanding roads to avoid congestion during a wildfire. Others might argue that removing people from the WUI will protect the beauty of undeveloped lands and save lives. The challenge with this approach is prioritizing the virtues of the townspeople. Lastly, the common good approach helps illuminate the subject further, as we will see in the next section.

Making a recommendation

Given that wildfires affect everyone equally within a certain distance, an appropriate solution should be one that “best serves the community as a whole”, that is, the common good approach [8].  One solution could be to limit any further housing development in WUI areas. Researchers have found that housing in the WUI has grown faster than the WUI itself [9]. Adding human settlements to the WUI increases the number of potential deaths and property losses.  On the other hand, residents already present in the WUI should take preventive measures by making their homes fire resistant and attending workshops organized by fire officials. Risk assessments should also be instituted and conducted by professionals. Research suggests that there is a gap between the perceived risk to wildfires by homeowners and professional examiners [11]. Closing this gap could help homeowners make their property more fire resilient. Furthermore, for residents from lower incomes, government assistance should be provided in the form of subsidized retrofitting projects. This would ensure that even those who are most vulnerability can still protect their homes and prevent a fire from spreading to other homes. Since people tend to rebuild in the same place after a wildfire, stringent policies should also be enacted that require new homes to be designed with wildfires in mind [10]. This could entail assisting residents with purchasing fire resistant materials, shifting the location of the house, or altering the landscape to mitigate fire risk. Officials should also make it easier to rebuild such homes by expediting permits or by providing a database of resources that can facilitate the reconstruction process. In addition, if housing is allowed to expand in the WUI, then it should be allowed in areas classified as the interface. This is because it is more challenging to protect dispersed settlements (intermix WUI) than it is to protect a cluster of homes (interface) [9]. Intermix areas put a higher strain on fire responders by requiring resources to be spatially divided, thereby limiting the ability to stop a wildfire. Building in interface areas would also be more beneficial to the greater common good by allowing residents to form more cohesive social networks in order to prepare for wildfires. These networks might be more difficult in intermix areas where homes are spread out and residents might be less likely to build relationships with each other.


The increasing number of settlements in the WUI is a cause for concern as the frequency of wildfires continues to increase. These communities face a higher risk for wildfire and should follow measures to mitigate the impact of a wildfire. Many people choose to live next to nature because of the benefits associated with pristine areas. The index tool that I created can be used to gauge the level of vulnerable populations by census tract. This could be used to focus attention on tracts with high scores thus allowing communities to prepare more effectively for a wildfire. The role of housing in the WUI plays an important role in limiting the number of human settlements and therefore lives that might be lost to wildfires. Unfortunately, the housing crisis affecting the Bay Area and California as a whole poses a limitation on a solution based around reducing housing in the WUI.  Therefore, exploring the role of government and planning officials in housing outside the WUI appears to be an interesting next step.


[1] CAL FIRE. (2019). Incident Information. Retrieved March 12, 2019, from

[2] Watts, J. (2018, July 30). The Swedish town on the frontline of the Arctic wildfires. The Guardian. Retrieved from

[3] Chuck, E. (2017). Land of ice and fire: Historic wildfire in the Arctic has burned for weeks. Retrieved March 12, 2019, from

[4] Stewart, S. I., Radeloff, V. C., Hammer, R. B., & Hawbaker, T. J. (2007). Defining the Wildland–Urban Interface. Journal of Forestry, 7.

[5] Radeloff, V. C., Helmers, D. P., Kramer, H. A., Mockrin, M. H., Alexandre, P. M., Bar-Massada, A., … Stewart, S. I. (2018). Rapid growth of the US wildland-urban interface raises wildfire risk. Proceedings of the National Academy of Sciences, 115(13), 3314–3319.

[6] Cutter, S. L., Boruff, B. J., & Shirley, W. L. (2003). Social Vulnerability to Environmental Hazards*. Social Science Quarterly, 84(2), 242–261.

[7] Dyer, C. B., Pickens, S., & Burnett, J. (2007). Vulnerable Elders: When It Is No Longer Safe to Live Alone. Jama, 298(12), 1448. doi:10.1001/jama.298.12.1448

[8] A Framework for Ethical Decision Making (2015). Retrieved April 13, 2019 from

[9] Hammer, R. B., Radeloff, V. C., Fried, J. S., & Stewart, S. I. (2007). Wildland - urban interface housing growth during the 1990s in California, Oregon, and Washington. International Journal of Wildland Fire, 16(3), 255.

[10] Alexandre, P. M., Mockrin, M. H., Stewart, S. I., Hammer, R. B., & Radeloff, V. C. (2015). Rebuilding and new housing development after wildfire. International Journal of Wildland Fire, 24(1), 138.

[11] Meldrum, J. R., Champ, P. A., Brenkert-Smith, H., Warziniack, T., Barth, C. M., & Falk, L. C. (2015). Understanding Gaps Between the Risk Perceptions of Wildland-Urban Interface (WUI) Residents and Wildfire Professionals: WUI Residents and Wildfire Professionals. Risk Analysis, 35(9), 1746–1761.

Link to Index too: 

Aug 27, 2019