ESTES PARK, Colo. - Strong, gusty winds have increased the fire activity at the Fern Lake Fire in Rocky Mountain National Park.

The fire has burned 979 acres and is 30 percent contained.

"In anticipation of predicted warm and windier weather today, fire managers have ordered a heavy helicopter to assist with suppression efforts," officials said Tuesday.

The helitanker carries 1000 gallons of water at high altitude and will be used in addition to the smaller helicopter currently being used for reconnaissance.

Over the past three days , the fire has moved through scattered dense stands of live trees, towards the center of the park, resulting in more smoke in the area than seen last week, officials said.

 The fire is burning in steep, rugged terrain with beetle killed trees making it too dangerous for firefighters to conduct a direct attack.

The Cub Lake Trail, Fern Lake Trail, and Fern Lake access road (beyond the winter parking) remain closed. All access to the Ute Trail is closed, including from Upper Beaver Meadows. Lower Odessa Gorge (north of Odessa Lake) is closed to all use. Other trails leading into the fire area are closed and are posted.

The cause of the fire is still under investigation.

"If you were in the vicinity of the Cub Lake Trail and/or the Fern Lake Trail any time before 2 p.m. on Tuesday, October 9 you may have pertinent information," officials said. "If you saw anything unusual or noteworthy, investigators would like to talk with you."

Tipsters can contact the National Park Service at 970-586-1399.