Firefighters were bracing Sunday for warmer and drier weather in the coming days as they battled to protect hundreds of ancient sequoias threatened by flames raging across rugged and parched terrain in Yosemite National Park.

The Washburn fire had grown to at least 1,591 acres and was burning on the southern end of the park near the historic Mariposa Grove, home to about 500 giant sequoias, officials said. The blaze is also threatening the community of Wawona and prompted officials to close Highway 41 near the south entrance to Henness Ridge Road.

Fire officials said that rising temperatures and dry weather were predicted for much of the week, creating the potential for flames to spread quicker and making an already difficult task even more challenging for crews fighting the blaze.