LOS ANGELES — Campsites and lodges emptied out after disappointed tourists were ordered to leave the heart of Yosemite National Park by noon Wednesday, as firefighters battled to contain a huge wildfire just to the west that has threatened the park’s forest and sent up smoke that obscured grand vistas of waterfalls and sheer granite faces.

Yosemite Valley will be closed until at least Sunday, along with a winding, mountainous, 20-mile stretch of California’s State Route 41 that leads in,