ALONG THE GUNFLINT TRAIL, Minn. - Shifting winds prompted another mandatory evacuation Thursday in northeastern Minnesota - and nearly half of the scenic Gunflint Trail was closed - as a wildfire continued to push its way eastward, sending a menacing cloud of smoke into the sky and raising anxiety among residents.

When the winds began blowing from the northwest Thursday afternoon, the sheriff ordered the evacuation of the area around the landmark Gunflint Lodge, which is just east of the scenic Gunflint Trail that leads from Grand Marais into the wilderness.

Bill Paxton, a spokesman for the firefighting effort, said the fire was "challenging" the containment lines. "They're holding right now," he said. "We're having some difficulty holding them, but they're holding now."

The fire has already destroyed 45 structures. The shifting winds put another 100 buildings at risk, fire officials said. At least 34 square miles had burned by Wednesday, the latest update available, and from the air, the land looked brown and barren.

However, no one had been hurt since the fire started to burn on Saturday at a campsite on remote Ham Lake.

Paxton said the winds were gusting up to 20 miles an hour Thursday and the air remained hot and dry. Fire officials called Thursday a "red flag" day for fire danger in and near the protected Boundary Waters Canoe Area Wilderness.

"It has explosive potential - probably as great as you'll ever see around here," said Steve Raddatz, an operations sections chief on the fire.

Near the rustic Gunflint Lodge, on the south side of Gunflint Lake, huge clouds of smoke and active flame were seen billowing from the sky. Miles down the Gunflint Trail, the northern sky had turned a deep slate blue color, much like that of an incoming thunderstorm. Between dark cloud and the trees, a ribbon of glowing orange from the fire could be seen.

The Gunflint Lodge was founded in 1925 deep in the wilderness of northeastern Minnesota at what was then the end of the Gunflint Trail. It's remoteness was always part of its allure. Over the years it evolved from a rustic fishing resort to a luxury vacation destination, popular as a jumping off point for excursions into the nearby Boundary Waters Canoe Area.