Why are fires so much scarier, bigger, and more destructive than they have ever been?
It is important to recognize that it isn’t attributable to one thing. At this point, there are a number of things that are cumulatively causing much worse wildfires. The factors CalWild would highlight (not in a particular order):
- A century of fire suppression and poor ecosystem health
- Climate change
- Development leading to more people living in high fire prone areas
Fire suppression and poor ecosystem health
The Big Blowup (or Big Burn or Great Fire) of 1910 set off a series of policy decisions at the U.S. Forest Service that concluded with the adoption of a 100% fire suppression approach to wildfires. This established a precedent followed by other public lands or firefighting agencies to a greater or lesser degree including the National Park Service, the Bureau of Land Management, and CalFire. It also set the stage for viewing fire in a combative, almost war-like, manner. Over 100 years of 100% fire suppression policies have led to an enormous buildup of fuel on our landscape.
For millennia, California’s indigenous people have intentionally set fire to the land. This is known as cultural or prescribed burning. By setting these low intensity fires at times of the year when they are less-likely to burn out of control, forests and other landscapes reduce their fuel loads and often create a cycle of re-birth for many plants. This is a very different way of understanding and working with fire than what we have been doing for the past century.
It is important to note that indigenous people were persecuted for continuing to practice cultural burning during this period. Only now is their knowledge of the land and its relationship with fire, which was in large part shaped by centuries of cultural burning, being appreciated.
Fire has been and will continue to be a part of California’s landscape. In fact, much of the state’s ecosystems have adapted and are dependent on fire for their health. When you combine the removal of fire on the landscape with logging practices, we have a recipe for catastrophic fires. Poor historical and ongoing logging practices have resulted in the removal of the largest, most fire-resistant trees. These big trees have been replaced by carpets of young trees and shrubs that are ready to burn. Logging also produces “slash,” or piles of bark, limbs, and other waste material that helps kindle the flames of unnaturally hot fires. As the University of California’s Sierra Nevada Ecosystem Project found in 1997, logging has increased fire severity more than any other human activity. From the perspective of forest health and resilience, there are too few large trees, too many small trees, and an excess of surface and ladder fuels that significantly increase the risk of high-severity wildfire.
Reintroducing fire on the land with preferred methods at times that are mostly within our control is the only way to restore many of these ecosystems. Historian Stephen Pyne summarized it best, “we thought we were putting out fires, when in reality we were merely putting them off.”
The science of climate change is settled. The world is getting warmer, humans are the cause, and we are going to see the impacts in changing weather patterns. California has already experienced significant warming across the state and temperatures have collectively risen about 1.8 degrees Fahrenheit since just 1980. California endured a serious drought from 2012-2017, which arguably has not ended to date. The changing climate may also change wind patterns known as the Diablo winds in Northern California and the Santa Ana winds in Southern California, which play an important role in the size of wildfires. Whether there will be an increase or a decrease in these winds is still to be determined. Finally, even in wet years, the snowpack of the Sierra Nevada which has historically been the greatest source of summer water, will increasing fall as rain, making dry seasons even drier.
Regional average temperature change in CA. Graphic by The Washington Post.
Each of these changes have increased the likelihood of megafires in California. Additional heat, particularly in the summer months, has increased the dry material on our natural landscapes and increased the length of the fire season. The most recent drought was also the major factor in the die off of millions of trees in the Sierra. Droughts stress landscapes and make them more vulnerable to other disturbances like the infestation of the bark beetle which added to the enormous die off. The significant winds across the state also contribute to the scary speed some of these fires have moved into communities. We repeatedly hear stories of communities having fire bearing down on them without any warning or emergency alert and residents scrambling to get out with their lives.
Ultimately, climate change is a multiplier and an accelerator of the other challenges we face. It makes the problem bigger, the solution harder to attain, and the consequences of inaction even greater.
Population growth in fire-prone landscapes
The California housing crisis has been crushing for most people, especially along socio-economic and racial lines. To find relief, many people are moving to areas with slightly more affordable housing. Those communities are by and large embracing that growth. While finding more affordable places to live is important, much of this development is happening in fire prone areas.
The wildland-urban interface or WUI (pronounce “woo-ee”) is a term that is now flying around news reports. This is the area where human structures are built in or adjacent to wild places. This reality is making our wildfires more common and more destructive.
With more buildings and people in high fire areas, the likelihood of greater damage and loss of life is higher. There simply are more people in areas that traditionally burned, but have not in decades, and are likely to burn again. In California, growth in the WUI has exploded and we now have about one in three houses in the WUI.
The reason why fire becomes more common with the growth of the WUI is that humans are the primary source of wildfire. Humans cause 80% of all wildfires. That number increases to 97% when you look at wildfires that burns structures.
The development and protection of WUI communities are not CalWild’s policy focus. However, it is impossible to acknowledge the impact of wildfire in California without outlining the enormous growth of communities in the WUI.


