JACKSON - Rugged terrain and large numbers of beetle-killed trees promised to complicate efforts to contain a wildfire that once again has closed the east entrance to Yellowstone National Park.

Trees killed by beetles were also providing plenty of fuel for a fire near Togwotee Pass in the Bridger-Teton National Forest.

On Wednesday, Yellowstone's Columbine fire had crept within just a couple hundred yards of the east entrance road at Sylvan Pass, and the short-term forecast called for erratic winds and warmer temperatures.

"We're going to have conditions today that are conducive to large fire growth," fire incident commander Mark Grant said.

It was bad news for late summer tourists staying in Cody or the many lodges between the town and Yellowstone. With the east entrance closed, the detour to get into Yellowstone through the northeast entrance on the Montana line is a long one - at least 29 extra miles.

The fire had burned more than 12,000 acres - nearly 19 square miles - just inside the park's eastern border. Cooler weather and higher humidity had tamed the fire a bit Tuesday, allowing the east entrance to reopen, but the fire flared up again around 4 p.m. and prompted closure later that evening. The gate remained closed Wednesday and was expected to be closed for at least several days.

Firefighters were focusing on keeping flames away from the east entrance road, which crosses a dry, south-facing slope. Just east of Sylvan Pass, the fire had crossed Middle Creek onto the narrow strip between the creek and the road, Grant said.

Firefighters were less concerned for the time being about scraping a barrier around the fire to keep flames from spreading in other directions. Grant said the steep terrain - and how as many as half of the area's trees are beetle-killed - makes venturing deep into the fire area a dangerous proposition.

Beetle kill has been a problem in much of the West following several consecutive mild winters, which have enabled bark beetles to survive from one summer to the next.

"It's going to be nearly impossible to get all the way around this thing," Grant said.

He said the fire likely would persist until there is a "season-ending event." In Yellowstone, that's often the first large snowstorm.

About 110 people were fighting the fire in different capacities. They had help from two water-dropping helicopters and eight fire engines.

The fire began with a lightning strike Aug. 9.

In the Bridger-Teton, the Hardscrabble fire near Togwotee Pass had burned 3,017 acres and was 50 percent contained, officials said Wednesday. They were watching to see if the fires intensified and moved even closer to U.S. Highway 26, which could trigger closure of the Togwotee Pass highway. The Wyoming Department of Transportation reported Wednesday the fire had burned to within half a mile of the highway.

That blaze also was burning in "extreme decadent fuel" resulting from pine beetle infestations.

Also on the Bridger-Teton National Forest, the Middle fire southeast of Alpine Junction has burned 2,900 acres and was 30 percent contained.

On the Bighorn National Forest, the Little Goose Fire which burned three structures early in the week was at 4,807 acres and 40 percent contained.

Four other fires were burning around Yellowstone but didn't threaten to close any roads or facilities. Two remote fires - a 1,000-acre fire on the Promontory Peninsula in Yellowstone Lake and a 1,500-acre fire east of the lake - were not being fought.

In northwest Yellowstone, firefighters were called in to fight a flare-up inside a 2,800-acre fire that had been declared fully contained several weeks ago, according to park spokesman Al Nash.

"With the type of weather and dry fuels we've had, there was a concern that it could produce a spot fire outside the containment line and we did not want that to happen," Nash said.

Firefighters expected Wednesday to contain an eight-acre fire a few miles east of the park's south entrance.

Because of the hot, dry conditions, Yellowstone officials have imposed fire restrictions beginning today. No wood or charcoal fires will be allowed in the backcountry of Yellowstone. This includes anything that produces an open flame such as fire grates, charcoal grills and fire pans.

Only portable camp stoves and lanterns which use white gas, kerosene, compressed gas, or similar fuels, and sheepherder-type stoves with spark arrester screens, may be used in the backcountry.

Wood fires and charcoal grills will be allowed in the frontcountry of the park only in designated fire rings or grates at picnic areas and in developed campgrounds.