Mesa Verde National Park administrators were forced to evacuate visitors on Thursday when a fast-moving, tree-hungry forest fire began climbing the mesa’s east wall.

Early reports said that the fire began when a tree that had been struck by lightning earlier in the week flared back up.

Will Morris, spokesperson for Mesa Verde National Park, said that the recommendation to evacuate came from fire-management officer Tim Oliverius and was put into action by park Superintendent Larry Wiese.

"The fact that there is only one road in and out of the park was the biggest factor in making the decision to evacuate," said Morris.

The spokesperson guessed that between 500 and 750 visitors were evacuated from the park after the decision was made at 3 p.m.

Morris said the evacuation went smoothly and visitors were "pretty relaxed" despite the dramatic-looking scene below the park’s twisting cliffside roadway.

"There is always some concern when drivers are going to be heading towards a large column of smoke and looking down onto the fire below," said Morris.

"Staff members told visitors that they were not in any danger and had plenty of time to leave the park and that they should obey the speed limit," he said.

"Ironically, (the park) had just updated its evacuation plan within the last two weeks — so the staff knew exactly what they needed to do," said Morris.

Morris added that between 100 and 150 national-park staff members were also within the park’s perimeters when the fire took off.

"We had several teams of archaeologists in the backcountry when the fire started spreading," Morris said.

"Those teams had about a 90-minute hike out of the backcountry, which is why we made the decision to evacuate so early," he said.

Morris said that as of Friday morning, no major archaeological sites had been threatened.

"We do have a dozen (Mesa Verde National Park) archaeologists traveling with the ground crews to help determine if there are sites near the fire area," said Morris.

Morris added that bulldozers are not allowed on the national-park land (as they could destroy artifacts) but have been used to cut fire-control lines on private property.

The spokesperson said that firefighters do have engines stationed at Morefield Campground on top of the mesa that will be utilized should the flames reach that high.

Morris said the park will remained closed until Mesa Verde administrators receive the go-ahead from the overhead fire team.

Along with the park evacuation, 20 nearby residences were also put on evacuation alert.

"Ten of those residences left voluntarily," said Morris.

Morris said Friday afternoon that flames had crept to within a 1/4 mile of some of those residences.