Over five thousand firefighters and two dozen aircraft are battling the Rim Fire, in California.
They have fought it to forty percent containment.
The fire has burnt over two hundred and twenty-three thousand acres, including forty-nine thousand in Yosemite National Park.
One hundred and eleven buildings, including thirty-one homes, have been lost to the flames.
Forty-five hundred homes and a thousand other buildings lie with a mandatory evacuation area, that is threatened by the blaze.
Hopes are that continued containment will allow for some evacuations to be lifted soon.
Winds continue to help the fire expand and drown nearby towns in smoke, making breathing difficult.
However, lower temperatures and higher humidity have aided in battling the fire.
Yosemite National Park has remained opened, the main part of the
park lies more than twenty miles away and authorities say that it is not in any danger.
Most worries are focused on the Hetch Hetchy Reservoir and the
O'Shaughnessy Dam, which are now less than half a mile from the flames.
San Fransisco gets eighty-five percent of it's water from the reservoir and significant amounts of power from the dam.
City officials say that they have adequate emergency reserves, should the water become reached by the smoke.
They are also doing hourly checks of water quality to ensure that
contaminants from the fire are not reaching people's drinking water.
Power supply has already been interrupted, as some power lines have fallen victim to flames.
