A National Park Service review of August's Big Meadow Fire in Mariposa County says that the prescribed burn plan was inadequate.
The fire, which began Aug. 26, was a prescribed burn that escaped and grew out of control, charring more than 7,400 acres near the community of Foresta. The fire was contained on Sept. 10.
The report says that the fire escaped into an area of brush and logs, which launched embers in many directions and made the fire too hot to fight directly. The logs and brush were left over from the 1990 A-Rock fire, the park service said.
The report says that the prescribed burn was scheduled for August, instead of times of cooler weather conditions, because there was a window of time when temperature, humidity, fuel type, wind speed and other requirements met certain conditions necessary for a prescribed burn. However, the prescribed fire plan was "inadequate" because the large area included various types of fuel, topography and environmental factors, the park service said.
Guidelines for fire planning are not clear on certain criteria, and may have led to the park service's underrating of the complexity of the prescribed burn, the report said.
The contingency plan was "overly optimistic for an in-season prescribed burn," the report said. The plan was based on a single-spot fire and called for the use of bulldozers to construct containment lines and helicopters to assist. However, multiple spot fires occurred and exceeded available resources, the report said.
The report also said that a prescribed burn plan called for use of a bulldozer in case the fire grew out of control, but park administrators made it clear to the burn boss that the bulldozer was not to be used without permission because of environmental concerns. When the escape occurred, the burn boss was unable to contact the person who could grant permission to use the bulldozer, resulting in a delayed decision to use the equipment.
The park service says that the area will regrow as chapparral, an area of shrubland with scattered patches of conifer pines. Eventually, Ponderosa pines, cedars and knobcone pines will return, the park service said.
A burned area emergency response team is still investigating the fire and developing a plan to address water quality issues and erosion.