The explosive Mosquito Fire burning in the foothills east of Sacramento, capital city of the western US' California, grew to 29,585 acres (119.7 square km) on Friday noon, some 60 hours after it was first reported on Tuesday evening.
"Today the Mosquito Fire showed extreme fire behavior and growth, more than quadrupling in size," the California Department of Forestry and Fire Protection (Cal Fire) said in its latest briefing, adding that aircraft continued to have difficulty accurately mapping the fire's perimeter due to heavy smoke, Xinhua news agency reported.
The blaze has continued to erupt in size, up from 13,700 acres (55.4 square km) reported Thursday evening and 6,900 acres (27.9 square km) Thursday morning.
Some 1,700 personnel were assigned to the huge wildfire as of Thursday evening, according to Cal Fire. The Forest Service said more than 260 bulldozers are working on the scene.
As of Thursday evening, local authorities said the blaze was threatening 3,666 structures in El Dorado and Placer counties, while Georgetown, a historic gold rush town of close to 3,000 residents, was listed on the evacuation map.
California Governor Gavin Newsom on Thursday evening declared a state of emergency for El Dorado and Placer counties due to the Mosquito Fire.
A state of emergency was also declared early this week in Riverside County for Fairview Fire burning in Southern California, which consumed 27,463 acres (111.1 square km) of land as of Friday noon.