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.

Authorities increased the size of the evacuation zone for the White Sage Fire north of the Grand Canyon on Friday morning.

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.

A mix of high temperatures, gusty winds, low humidity, and dry vegetation has fuelled the fire's swift advance, officials say.

Evacuations have been ordered for the area north of Jacob Lake, in northern Arizona, due to the White Sage Fire.

The Coconino County Sheriff's Office helped evacuate people from an area north of Jacob Lake and campers in the Kaibab National Forest nearby.

Dangerous heat and dry conditions fueling the White Sage Fire in Arizona have prompted authorities to expand evacuation zones to clear out the Grand Canyon.

The White Sage Fire was burning in Arizona bout 15 miles southeast of Fredonia in Coconino County and north of the Grand Canyon State Park.