A 1993 United States Forest Service study estimated that the extent of old growth in the Forest was . Wildfires are not uncommon in the National Forest. In September 2012, a severe lightning storm ignited hundreds of fires, the largest of which were located southwest of the city of Wenatchee and east of Blewett Pass. Significant wildfires occurred again in July 2014, in the Chiwaukum and Entiat Mountains. A lightning strike near Jolly Mountain on August 11, 2017 ultimately burned more than 38,000 acres and forced significant evacuations.