The night of August 8, 2024, the Canyon Fire ignited in the Tuolumne River Canyon, an area about 50 miles northwest of Yosemite National Park. Due to the abundance of wildfire fuel, the steep topography, and the limited number of roads in the area, the blaze quickly became a threat to the nearby subdivisions of Ponderosa Hills and Mira Monte, as well as the unincorporated community of Tuolumne City. Fortunately, the Tuolumne Fire Safe Council had anticipated the possibility of a severe wildfire and completed the Ponderosa-Mira Monte Shaded Fuel Break just two years prior. The fuel break gave wildland firefighters leverage in slowing and ultimately extinguishing the blaze, saving area homes and lives.
Conditions along Mira Monte Road prior to the project.
In 2019 the Tuolumne Fire Safe Council received a $415,000 grant through the Wildfire Prevention Grants program to construct the Ponderosa-Mira Monte Shaded Fuel Break. The Fire Safe Council’s objective, in taking on the project, was to connect two existing fuel breaks in an area that had never before been treated due to the steep terrain. Crews completed construction of the fuel break in January of 2022, removing dense vegetation across a 1.9-mile-long and 300-foot-wide area of forest. Workers were forced to complete approximately 44 acres of the 68-acre area by hand due to the extremely steep slopes. By extending fuel breaks in the area, especially over the steepest terrain, the Tuolumne Fire Safe Council aimed to provide a greater buffer of protection against severe wildfire for the nearby Ponderosa Hills, Mira Monte, and Tuolumne City communities.
Fuel conditions after the project was completed in the area.
The Ponderosa Hills and Mira Monte subdivisions are nestled along the Tuolumne River Canyon and consist of 345 and 27 homes, respectively. Both subdivisions have limited emergency services access, making it difficult for emergency response teams to enter and exit the area. The steep slopes surrounding both subdivisions are also populated with dense brush and scattered trees, providing the fuel and topography that worsen wildfire outcomes.
When the Canyon Fire broke out in the area, initial attack bulldozers and hand crews utilized the Mira Monte portion of the fuel break to establish control lines along the Western flank of the fire. When the fire reached the treated fuel break, fire intensity was significantly reduced, and the forward progression was slowed and eventually stopped. The next morning aircraft utilized the openings created by the fuel break to drop retardant and reinforce the control lines. After six days the Canyon Fire was declared 100% contained at 85 acres. No injuries or fatalities occurred, and no structures were lost.
Shows the treated fuel break with the retardant line. Note the steep terrain and the house at the top of the picture.
The Ponderosa-Mira Monte Shaded Fuel Break altered the activity and course of the Canyon Fire, saving structures and lives. The fuel break slowed the progression of the blaze and allowed crews to catch it before the environmental conditions, including rising temperatures, became less favorable and elevated fire activity. Had the fire reached the adjacent subdivisions, fire crews would have been forced to take defensive action and focus efforts on saving as many homes as possible. The Ponderosa-Mira Monte Fuel Break and the ensuing Canyon Fire that tested it demonstrate the effectiveness of these measures in protecting communities in high-risk areas.