By Dan Whitcomb
(Reuters) - Firefighters began to gain the upper hand on Monday against a Northern California wildfire that has destroyed 13 homes and blackened nearly six square miles in the drought-parched foothills east of Sacramento, officials said.
Crews had built containment lines around roughly two-thirds of the so-called Sand Fire as of Monday morning, up from only 35 percent on Sunday evening, the California Department of Forestry and Fire Protection said.
Some residents who were forced to flee their homes ahead of the flames, were allowed to return on Monday.
But CalFire cautioned that the blaze was still burning in steep, dry terrain that made fighting it more difficult and that they didn't expect full containment until Friday.
The Sand Fire, which erupted in the Sierra Nevada foothills east of Sacramento on Friday, has scorched more than 3,800 acres. There has been one minor injury to a firefighter.
Nearly 2,000 firefighters backed by air tankers have been deployed against the blaze, working in nearly triple-digit temperatures, high winds and extremely low humidity.
California is facing one of its most severe droughts on record, with wide swaths of the nation's most populous state under "exceptional drought," or the most severe rating issued by the U.S. Drought Monitor.
About 180 miles to the southeast, a 2,600-acre wildfire on the western edge of Yosemite National Park was about 5 percent contained on Monday and one structure had been destroyed, the U.S. Forest Service said.
The blaze was burning close to where the 2013 Rim fire seared some 250,000 acres in the central Sierra Nevada region.
(Reporting by Dan Whitcomb in Los Angeles; Editing by Eric Beech)