San Francisco, Sep 14 (IANS): The Mosquito Fire, currently raging in California's Placer and El Dorado counties, has grown to 49,761 acres, even though firefighters said they continued to make progress building and strengthening control lines around the blaze.

The Mosquito Fire, first reported on the evening of September 6, has so far destroyed 46 structures, damaged five structures and was still threatening 5,848 structures, the California Department of Forestry and Fire Protection (Cal Fire) said in its latest update on Tuesday.

It added that 11,260 people had been evacuated since the fire started.

Cal Fire also said the steep and rugged terrain of the blaze makes it difficult for crews to access the fire directly.

Moreover, the use of aircraft was limited sometimes due to the continued inversion layer over the fire area.

Video posted online showed several helicopters were used for water-dropping operations in the late afternoon hours on Monday and a Cal Fire Hawk helicopter continued to be available and utilized for night-time water-dropping missions.

Cal Fire hoped to fully contain the fire by Octpber 15.

However, containment is not a measure of how much of the fire is extinguished but rather a gauge as to how much of a line crews have around the fire perimeter to prevent the fire from spreading.