WildfiresCalifornia needs to rethink urban fire risk, starting with where it builds houses

By Max Moritz

Published 14 December 2017

With widespread damage to structures, the wildfires raging across southern California highlight the importance of where and how we build our communities and, in particular, how land use planning and better building codes can reduce our exposure to such events. Despite an aversion by some to land use planning, this strategy is simply common sense. It will also save lives and massive amounts of public resources over the long term. Where we do choose to develop and inhabit hazard-prone environments, it may be necessary to design communities with “passive survivability” in mind, or the ability to withstand the event and have water and power for a few days. This provides both the built environment and the people within some basic protection for a limited time. Strategies exist to lower the risk of fire in the current housing stock and to more carefully design and site future development where wildfires are possible. With increasing extremes expected as climate continues to change, officially recognizing this link and creating a safer built environment will only become more urgent.

Wildfires raging across southern California are causing evacuations of many communities and have destroyed hundreds of structures this month.

These fires follow the wind-driven Tubbs fire earlier this fall that blasted through densely urbanized neighborhoods in Northern California, causing dozens of fatalities and thousands of home losses. Stories from both fires of how fast the fire spread and how little time people had to evacuate are stunning.

With widespread damage to structures, these fires highlight the importance of where and how we build our communities and, in particular, how land use planning and better building codes can reduce our exposure to such events.

Despite how unusual the devastation appear in portions of these fires, we need to recognize that these structure-to-structure “urban conflagrations” have happened in the past and will happen again. Yet these fires revealed that we have key gaps in our policy and planning related to assessing risk in fire-prone environments.

What is increasingly clear to fire researchers like me is that losses on the human side are often driven by where and how we build our communities. This means we must learn to coexist with fire, if we are going to inhabit fire-prone landscapes, just as we adapt to other natural hazards. An essential step is to shift our perspective from a focus on hazard to one that more comprehensively includes human vulnerabilities.

Mapping risk
California is leading the way in mapping the danger that wildfires pose to human communities and, in particular, linking building codes to fire severities that may be expected in given location. The state’s Fire Hazard Severity Zone maps are an essential step in recognizing fire as an inevitable process that must be accommodated, similar to how we plan for floods, landslides, earthquakes and hurricanes.