Preventing Extreme Fire Events by Learning from History: The Effects of Wind, Temperature, and Drought Extremes on Fire Activity

The 2017 fire season in California was highly unusual with its late seasonal timing, the areal extent it burned, and its devastation to communities. These fires were associated with extreme winds and were potentially also influenced by unusually dry conditions during several years leading up to the 2017 events. This fire season brought additional attention and emphasized the vital need for managers in the western U.S. to have access to scientific information on when and where to expect dangerous fire events. Understanding the multiple factors that cause extreme wildfire events is critical to short and long-term forecasting and planning. Seasonal climate measures such as temperature and precipitation are commonly used to explain fire occurrence and impact. However, weather events that produce extreme winds and severe temperatures over short periods of time can also have substantial impacts on fire behavior. In addition, multi-year droughts may increase fire potential by decreasing the amount of moisture in vegetation.

 

The goal of this project is to investigate the range of factors that may explain the variation in annual fire activity in both forested and non-forested landscapes in California. These factors will include the longer-term effects of extended droughts and the shorter-term effects of intense heat spells, low relative humidity, and extreme winds. In addition, researchers will evaluate the extent to which large fires are associated with particular fire ignition sources. Results should inform improved predictive models to show how long-term drought events and short-term extreme weather could impact future fire activity.

 

This project will evaluate the relative importance of these environmental factors over the last several decades, across different landscape types in California. Results will provide predictive tools for fire managers, enabling them to better anticipate extreme fire events and update fire-danger warnings. In the long-term, these results can also be used to inform efforts to understand possible changes in the probability of fire in California.