Fire officials also warned caribou hunters to stay away from areas off the Steese and Taylor highways.
A temperature inversion kept smoke low to the ground and made assessing new burned acreage difficult. However, it did help keep fire from spreading toward Central, a community of about 115 northeast of Fairbanks near the end of the Steese Highway.
``It's probably better than it would be if the inversion would lift,'' said fire information officer Pete Buist.
The inversion also limited Taylor Highway fires to moderate activity. The Boundary fire north of Fairbanks ``is not showing a lot of activity,'' Buist said.
An inversion is a weather condition in which temperatures increase as altitude increases. Clean air up high does not mix with cooler, smoky air below.
To get rid of an inversion, which tends to trap smoke, the lower atmosphere must warm up.
The National Weather Service predicted winds would switch from the northeast to the southwest, which would push fires away from Central. As of late afternoon, they had not arrived, Buist said.
``Visibility is still a huge problem there,'' he said.
Six fires making up the Central Complex have burned 260,000 acres. So far 15 structures have burned - seven homes and eight other buildings, primarily outbuildings such as sheds, shops or barns, Buist said.
As of 10 p.m. Tuesday, 261 firefighters were assigned to the fire and the number was to increase Thursday. A Type 1 management team, one of 16 in the country trained to manage complex fires, was getting a briefing at Fort Wainwright and preparing to head for Central. The crew of about 60 from Montana was to replace a Type 2 management team with 20 to 30 people.
``We expect them to take command of the fire sometime tomorrow,'' he said.
The fire within the complex causing the most concern was the Bolgin Creek fire, which has burned to the outskirts of Central and touched near the Steese Highway in several places. The highway remained closed between Central and Circle 34 miles away on the Yukon River.
As of Wednesday, the Bolgin Creek fire had consumed 64,700 acres and conditions remain extremely dry. With northeast wind and the visibility problem, ``That's all a recipe for not getting a handle on the fire quickly,'' Buist said.
An airplane with infrared equipment to assess burning acreage was to fly Wednesday night.
``We should have better information by tomorrow morning,'' Buist said.
Buist said the fire information center was taking lots of calls from hunters interested in pursuing the Fortymile caribou herd.
With the heavy smoke, he said, such hunts probably would be fruitless as well as dangerous.
