The White Sage Fire in Kaibab National Forest and the Dragon Bravo Fire near Grand Canyon National Park. The White Sage Fire, which started on July 9, has already scorched more than 20,000 acres of land and has not yet been contained, authorities said.

The White Sage Fire is nearly 20,000 acres, growing almost 40 times in size in over 48 hours as the nearby Dragon Bravo Fire grows to 5,000 acres.

Hurricane Valley firefighters have been deployed to the White Sage Fire, which is exhibiting “extreme fire behavior” as it covers over 40,000 acres near Grand Canyon.

Access via the North Rim, a lesser-used gateway to the national park, was closed as the White Sage fire continued to burn on Saturday.

A wildfire burning in Grand Canyon National Park triggered a chlorine gas leak Friday afternoon after flames reached a water treatment facility.

Hundreds of visitors and residents were evacuated from the North Rim of Grand Canyon National Park this week as two wildfires advanced toward the park.

Visitors and staff at two national parks in the U.S. West have been evacuted because of wildfires. Officials at Black Canyon of the Gunnison National Park in Colorado say the park closed Thursday morning after lightning sparked blazes on both rims.

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The NPS recommends avoiding hiking the Grand Canyon's inner trails between 10 a.m. and 4 p.m., when temperatures are at their peak. Temperatures in the inner canyon can reach over 120 degrees Fahrenheit in the shade, creating "extremely hazardous conditions for hikers," the NPS said.