Wildfires are a natural part of plant communities in the San Gabriel River watershed . However , after the flood of 1938 an intense program of wildfire suppression began , since burned areas tend to erode quickly during storms , causing landslides and mudflows down tributary canyons . Like many other areas of the western United States this has caused a large amount of tinder and debris to accumulate , increasing the risk of fire . Drought conditions in the first decade of the 21st century led to huge fires much larger than would have occurred naturally . In 2002 the Curve Fire burned , much of it in the North Fork of the San Gabriel River , closing Crystal Lake Recreation Area for several years . The 2009 Station Fire , the largest wildfire in Los Angeles County 's history , was mostly concentrated west of the San Gabriel watershed , but did burn much of the upper West Fork . With urban development expanding toward mountain areas , the threat of property damage continues to increase
Station Fire
Station Fire (2009)
San Gabriel River (California)