HELENA, Mont. — Hotels and campgrounds in Glacier National Park are flooded with calls from worried tourists canceling their reservations or asking whether the Montana landmark will stay open as a wildfire sweeps through a popular part of the park.

Hotel owners are trying to talk callers out of changing their plans, while Glacier officials emphasized that only a small part of the 1,718-square-mile park is closed as the flames chew though parched conifer-topped ridges on its eastern side.

The blaze has shut down nearly half of the heavily trafficked Going-to-the-Sun Road, and officials were helping reroute tourists planning to visit attractions along the road to other scenic areas.

The fire was unchecked and estimated at 6 square miles Friday, although fire spokeswoman Jennifer Costich said new information would soon provide a more accurate size. Some 300 firefighters dug fire lines, cleared debris and tried to stop the blaze from spreading northeast toward populated areas.

Blazes also are threatening homes in California and Washington state.