Dynamics and Risks

Fast-moving, highly destructive debris flows triggered by intense rainfall are one of the most dangerous post-fire hazards. The risk of floods and debris flows after fires increases due to vegetation loss and soil exposure. Cases of sudden and deadly debris flow are well documented along the western United States, particularly in Southern California. These flows are a risk to life and property...

WERC scientists are defining the past, present, and future of wildfires for wildlife and human communities. Explore this webpage to learn about specific, ongoing projects across California and parts of Nevada.

USGS Earth Resources Observation and Science (EROS), in conjunction with the US Forest Service Pacific Southwest (PSW) Region, has developed several new products for understanding and forecasting the probability of large wildland fires on all land in the conterminous U.S.

Big sagebrush plant communities are important and widespread in western North America and are crucial for meeting long-term conservation goals for greater sage-grouse and other wildlife of conservation concern. Yet wildfire is increasing in the West, turning biodiverse, shrub-based ecosystems dominated by sagebrush into grasslands containing invasive species such as cheatgrass and less overall pla

Fire size, frequency, overall area burned, and severity are increasing across many vegetation types in the southwestern U.S. In many cases, large contiguous areas are burning repeatedly at high severity, triggering vegetation type conversions (VTC), where once-dominant coniferous forests fail to return to their pre-fire state, often transitioning to shrub- or grass-dominated systems. Loss of these

Every year, wildfires devastate the landscapes of Southern California from Los Angeles to San Diego. How has a higher number of human-caused fires affected fire hazards and threats to resources? WERC’s Dr. Jon Keeley and collaborators are analyzing fire patterns across the state to help cities balance their management of fire hazards and natural resources.

Fuel loads are important drivers of fire behavior, and fire is an important natural process that can also be used as a tool for ecological restoration purposes. Land managers and fire experts attempt to track and manipulate fuel loads in order to assess fire risk, control fire behavior, and restore ecosystems. Thus, understanding the relationships between fire, vegetation dynamics, and fuel loads...

Mitigation of ecological damage caused by rangeland wildfires focuses on conservation of ecosystem function through reducing soil erosion and spread of invasive plants. The overall effectiveness of these treatments is variable, and their necessity has been debated recently. We conduct research projects and synthesize findings to determine if mitigation treatments: 1) protect ecosystems against...

Land managers have invested considerable funding to decrease fuel loads and restore resilient ecosystems in forests and rangelands, using techniques such as grazing, mowing, herbicides, and thinning. Yet, little information is available about how such restoration activities have influenced wildlife species and habitats. We are conducting empirical studies and developing novel approaches to better...

How will increased drought affect forest fire severity? WERC’s Dr. Phil van Mantgem is testing the idea increased drought stress may affect forest fire severity independent of fire intensity. Drought stress prior to fire can affect tree health, potentially resulting in a higher sensitivity to fire-induced damage. Thus, with drought there may be ongoing increases in fire severity (the number of...

Fuel conditions and fire regimes in western forests and deserts have been altered due to past land management, biological invasions, and recent extreme weather events and climate shifts. These changes have created extreme fire risk to local and regional communities, threatening their economic health related to wildland recreation, forest production, livestock operations, and other uses of public...

Large wildfires have raged across the western Americas in the past decade including the Las Conchas, New Mexico fire that burned 44,000 acres in a single day in 2011 (Orem and Pelletier, 2015, Geomorphology 232: 224-238, and references therein), the 2016 Fort McMurray, Alberta fire that required evacuating an entire city, and the 2015 Alaskan fire season that burned more than 5 million acres...