Yosemite fire 'poses every challenge there can be'

Hundreds of firefighters have been deployed to protect mountain communities in the path of a fire raging north of Yosemite National Park, as fierce winds gust on Sierra mountain ridges and flames jump from treetop to treetop.
Winds gusting to 50 mph (80 kph) and movement of the fire from bone-dry brush on the ground to 100-foot (30-meter) oak and pine treetops have created dire conditions.
"A crown fire is much more difficult to fight," Daniel Berlant of the California Department of Forestry and Fire Protection, told The Associated Press Sunday. "Our firefighters are on the ground having to spray up."

Overnight the fire grew 7 square miles (18 square kilometers) as firefighters gained little ground in slowing the now 207-square-mile (536-square-kilometer) blaze, Berlant said. The fire is covering an area about the size of Chicago.
"Today, unfortunately, we are expecting strong winds out of the south," he said. "It's going to allow the fire to advance to the northeast."
Fire officials are using bulldozers to clear contingency lines on the Rim Fire's north side to protect the towns of Tuolumne City, Ponderosa Hills and Twain Hart. The lines are being cut a mile ahead of the fire in locations where fire officials hope they will help protect the communities should the fire jump containment lines.

Officials estimate containment at just 7 per cent.

The blaze sweeping across steep, rugged river canyons quickly has become one of the biggest in California history, thanks in part to extremely dry conditions caused by a lack of snow and rainfall this year.
Investigators are trying to determine how it started Aug. 17, days before lightning storms swept through the region and sparked other, smaller blazes.
Statewide more than 8,300 firefighters are battling nearly 400 square miles (more than 1,000 square kilometers) of fires.
Many air districts have issued health advisories as smoke settles over Northern California.
The Rim Fire has threatened two groves of giant sequoias that are unique the region, prompting park employees to clear brush and setting sprinklers.

The towering trees, which grow only on the western slopes of the Sierra Nevada and are among the largest and oldest living things on earth, can resist fire. However, dry conditions and heavy brush are forcing park officials to take extra precautions in the Tuolumne and Merced groves.
The tourist mecca of Yosemite Valley, the part of the park known around the world for such sights as the Half Dome and El Capitan rock formations and waterfalls, remained open, clear of smoke and free from other signs of the fire that remained about 20 miles away.