San Francisco - Despite a relentless heatwave, fire crews reported significant progress Thursday on the fires that have devastated California for the last three weeks.

In the most serious blaze, which burned some 50 houses in the town of Concow Tuesday, authorities said the Camp Fire was 45 per cent contained Thursday. Overnight work in creating firelines had also reduced the threat to the town of Paradise, where 14,000 residents were ordered to evacuate Wednesday.

"A lot of progress was made in the Concow area and along the Feather River," said Mike Mohler, a fire information officer for the California Department of Forestry and Fire Protection. Some 2,900 firefighters were working the blaze in temperatures approaching 40 degrees that are expected to last till the weekend.

Firefighters also reported progress on the Basin Complex Fire that threatens the popular tourist town of Big Sur. That was pronounced 41 per cent contained Thursday up from 14 per cent Wednesday. It has destroyed 27 homes and 41 structures and caused thousands to evacuate along a 75 kilometer stretch of the Pacific Coast. The state's other major fire in Goleta north of Santa Barbara remained 55 per cent contained.

In total 322 fires are still burning across the state, with emergencies declared in 11 counties. According to state firefighting authority Cal Fire, more than 313,000 hectares have burnt since a freak barrage of lightning storms ignited over 1,400 fires on June 20 and June 21. Some 18,500 firefighters are battling the blazes, aided by over 100 water-dropping aircraft and 1,500 fire engines. In all 99 homes have been lost.

The threat to California prompted US Senator Dianne Feinstein to seek 910 million in emergency federal funding today for fire suppression, hazardous fuels reduction and rehabilitation projects.

"The situation in California is explosive," Feinstein wrote in a letter to the Senate Appropriations Committee. "Excessive-heat warnings have been issued, more dry-lightning strikes are expected, our resources are stretched to the breaking point and the state remains tinder-dry."

Firefighters were faring better in two other major blazes. In Goleta, north-east of Santa Barbara, the 4,000 hectare Gap Fire was declared 50 per cent contained, while progress was also made on the Basin Complex Fire threatening the tourist town of Big Sur. The fire was 35 per cent contained Wednesday and appeared to be moving away from the scenic coastal town. (dpa)