The fire burning on Glacier National Park's east side may have been started by people.

"Initial evidence suggests that the Reynolds Creek Fire was caused by human actions," park spokeswoman Denise Germann said in a news release Wednesday morning.

The National Park Service is seeking information that may assist with an investigation of the fire that erupted in mid-afternoon July 21 and since has burned 3,170 acres.

Park visitors hiking in the area of Reynolds Creek on the Gunsight Pass Trail or who may have been staying in or hiking through the Reynolds Creek Backcountry Campground from July 14 to July 21 are encouraged to call (888) 653-0009 or email nps_isb@nps.gov.

The fire was first reported around 3:45 p.m. on July 21, approximately 6 miles east of Logan Pass.

It spread quickly that afternoon and began a march north of St. Mary Lake, leading to evacuations and the closure of Going-to-the-Sun Road on the east side of the park.

The road from the west side re-opened to Logan Pass on Wednesday morning.

The fire was 56 percent contained as of Tuesday night, but firefighters on Wednesday were bracing for a return of high winds. A red-flag warning was in effect Wednesday for the fire area.

Firefighting efforts so far have cost $5.1 million. A firefighting force of 670 people, backed by seven helicopters and 23 engines, has been working on the fire.

The helicopters have dropped more than 1 million gallons of water on the fire.