Lighter winds and cooler temperatures have been a big aid to firefighters across California fighting major wildfires. Officials say about 1,400 firefighters have made significant progress against the largest of the fires, which has covered 21,760 acres east of Yosemite National Park. That firefighting effort claimed the lives of three crew members of a plane that was carrying fire retardant when it crashed Monday near Walker. So far the blaze is reported about 15% contained, with full containment not expected until next week. Fire information officer Brigette Baslee said the Marine Corps and U.S. Forest Service were conducting a joint investigation, to determine if a campfire built by Marine mountain warfare trainees may have started the blaze.