While it is common for vast sections of Alaska wild lands to ignite and smolder under the extended summer daylight, this year's fires have been driven by unusually hot and parched weather and plentiful lightning strikes.

In a typical summer, 500,000 to 1.5 million Alaska acres burn, according to statistics from past years. And usually, fire is part of the natural cycle that clears black spruce and white spruce, slender, fast-growing conifers with high levels of flammable resin, out of the way for slower-growing hardwood trees like birch and aspen.

Six hundred fires have burned during the summer, topping the 4.94 million acres charred in 1957, the previous record Alaska wildfire season.

As of Tuesday, 103 fires were still burning, including the 1.1 million-acre Taylor Complex fire that was created when several blazes merged. About 50 buildings had been lost, including seven homes, and 1,075 firefighters were on duty, with about $30 million spent fighting the fires so far.

Fire managers were still waiting for the heavy rains that usually douse Alaska's blazes by August.

"We didn't get that ground-soaking, long-duration rain," said Andy Alexandrou, a fire information officer with the federal-state Alaska Interagency Coordination Center.

Scientists warned that Alaska's trend is for increased wildfires of this magnitude.

"Most of the explanations trace themselves back to the climate change," Juday said.