What started out Monday as a prescribed burn turned into a wildfire of roughly 1,000 acres at Wind Cave National Park in South Dakota.

Officials said a "fire whirl," or "dust devil" swept through the Unit 2 Cold Brook Burn late Monday morning and carried burning ash more than 100 yards outside of the planned burn area and into high grass.

"Pushed by high westerly winds, the fire quickly moved beyond containment efforts," a park release said.

Fire engines and hand crews were brought in from outside agencies to assist firefighters already on the ground; in addition, air resources were ordered, including two South Dakota Air National Guard Blackhawk helicopters and a Single Engine Air Tanker (SEAT).

Late Monday afternoon, the fire was still within the park boundary. It was burning in the “keyhole” area of the park, land acquired by the park in 2011. There were 70 people assigned to the fire with no estimated time of containment.