The 2012 Washington wildfires were a series of 1,342 wildfires that burned 259,526 acres (1,050 km2) over the course of 2012. The fires primarily occurred in the Okanogan and Wenatchee National Forests during September and October 2012. A severe lightning storm on September 8 caused hundreds of fires across the east side of Cascade Range. Smoke caused hazardous air quality conditions in the cities of Ellensburg and Wenatchee, and was noticeable in Seattle. The cost of fighting the largest four fires was estimated to be $67.5 million.