Acres: 20,687 Start date: May 31, 2013 Cause: Downed powerline Location: Valles Caldera National Preserve, NM Containment: 40 percent Fuels: Mixed conifer and Ponderosa pine Terrain: Steep, rugged Resources: 21 crews, 52 engines, 35 water tenders, 2 dozers Total personnel: 1,023 Available air support: 3 air tankers, 6 helicopters Fire intensity increased significantly along the slopes just west of the Valles Caldera headquarters historic district yesterday afternoon. To slow its progress, aerial burnout operations began just before sunset along a ridge southwest of the established fire.