SANTA ROSA, Calif. (AP) – The secretary of the Department of Homeland Security says the federal government is helping to remove thousands of tons of debris as part of rebuilding efforts in wildfire-ravaged areas of Northern California. Wildfires that swept through Sonoma, Napa, Mendocino and Yuba counties in October killed 44 people and destroyed more than 5,000 homes. State officials say insured damages alone topped $9 billion. Secretary Kirstjen Nielsen says the blazes also left behind more than 700,000 tons of debris. Nielsen spoke Wednesday in the hard-hit city of Santa Rosa, where she surveyed the destruction and met with survivors. On Tuesday, she flew over areas of Southern California devastated by the largest wildfire in California’s modern history. The Thomas fire has destroyed more than 1,000 buildings in Ventura and Santa Barbara counties.