Greg Toppo

USATODAY

Travelers to Yellowstone National Park were being warned about hazards on area roads Sunday as firefighters worked to extinguish a wildfire blocking an entrance to the popular park.

The fire, which began last month in neighboring Grand Teton National Park, was blocking Yellowstone's south entrance, near the resort town of Jackson, Wyo. Wildfire managers were letting the fire continue to burn on Jackson Lake's west side, where no buildings or people are threatened, The Associated Press reported.

National Park Service officials said fires had forced the closure of U.S. Highway 89 between Yellowstone and Grand Teton, but both parks remained open to visitors. Fire managers on Sunday anticipated being able to reopen the highway by Tuesday but said that decision could change depending on weather and fire conditions.

Firefighters chopped down trees and searched for hot spots on steep hillsides as they battled the fire, after strong winds blew down several trees Saturday, blocking some roadways, AP reported.

Park officials were monitoring about a dozen fires in western Wyoming and eastern Idaho, including the Maple Fire, which was burning on Yellowstone's west side. It had burned 31,405 acres as of Sunday.

Fire crews were working on a fuel break on the park's western boundary to help reduce the risk of wildfire for the community of West Yellowstone, Mont., about four miles from the fire.

Linda Burroughs, a visitor from Russell, Pa., who was traveling with a group of senior citizens, said the wildfire cut short their planned two-day visit to Yellowstone. They had to take a four-hour detour to get to their Jackson Lake lodge, south of the Grand Teton fire.

"We see the smoke off and on," she said, but the fire wasn't threatening tourists at the lodge.

Follow Greg Toppo on Twitter: @gtoppo