Since 2000, the wildfire season has grown longer and more severe. A record 10.125 million acres were burned by wildfires in 2015, breaking the record set in 2006, said the USDA, which spent $2.6 billion on firefighting, its most expensive fire season ever. Thirteen firefighters were killed and 4,500 homes and other structures were destroyed. In an inventory of the fire season, the department said 20 fires consumed more than 100,000 acres each and an additional 30 fires exceeded 50,000 acres apiece. Slightly more than half of the Forest Service budget was spent on fires. The Forest Service says it frequently has to reduce spending on forest restoration and fire prevention in order to put the money into firefighting.