Alaska’s million-acre wildfire season, typical in size, had some unusual features

Alaska wildfires burned more than 1 million acres this year, putting the 2025 season at about the average for recent decades.

Alaska fire seasons of more than 1 million acres have become more frequent since about 1990, records show. Since then, 1 million acres is in the “near-normal category,” said Rick Thoman, a scientist with the Alaska Center for Climate Assessment and Preparedness at the University of Alaska Fairbanks.

But it was an unusual season in some ways, Thoman said.

The season started slowly, with only 38 acres burned in early June, a notably cool period, he said. That was despite concerns that a lack of snow in Southcentral Alaska would bring about an early fire season.

The slow start shows the importance of weather patterns to wildfire fire starts, he said. Fires start in dry, warm and windy conditions, with some kind of spark, he said. “You need all the ingredients,” he said. “Some of the ingredients don’t work – you need all of them.”

Fire activity then exploded later in June, thanks to over 80,000 lightning strikes around the time of the summer solstice. Between June 15 and June 29, there were 162 new lightning-caused wildfires in Alaska, according to the U.S. Bureau of Land Management’s Alaska Fire Service.

Another unusual feature of the season was the number of big wildfires that burned simultaneously near population centers, prompting some evacuations and strains on firefighting resources.

A pair of fires called the Nenana Ridge Complex burned over 32,000 acres and prompted evacuations in the area between Fairbanks and Nenana. Other Fairbanks-area fires burned as well. The Bear Creek Fire and St. George Creek Fire in the Denali Borough together totaled about 71,000 acres, and some residents’ homes were burned. There were also fires near Tok and Delta Junction in the eastern Interior region.

For Fairbanks-area residents, wildfires brought another season of smoky skies.

Though the smoke was not especially heavy, this summer was the fourth in a row in which it caused at least 100 hours of reduced visibility at the Fairbanks International Airport. That is an unprecedented series, Thoman said.

“Prior to this streak, there had never been more than back-to-back summers with 100 hours or more,” he said.

Some northern fires were noteworthy.

The 307-acre Fortymile Fire in the Yukon Flats National Wildlife Refuge was suppressed as part of a new strategy to protect ice-rich permafrost and prevent carbon emission caused by thaw.

There were also several fires in the treeless tundra of the North Slope, a region where fires have been limited in the past by normally moist conditions and a lack of flammable vegetation. Most of the North Slope tundra fires were small, but there were two substantial fires: the Ikpikpuk Fire, which burned about 2,000 acres, and the Bronx fire, which burned about 618 acres.

In all, 458 wildfires had burned over Alaska’s season, as of Tuesday, according to the federal-state Alaska Interagency Coordination Center.

Alaska’s fire season may not be entirely over.

One fire at the Alaska-Canada border, estimated at 0.5 acres as of Tuesday, was attributed to a lightning strike that occurred about two weeks ago. The fire was burning in dense spruce and is an example of lingering fire risks in eastern Interior Alaska, fire managers said.

In recent days, dry and windy conditions led to a series of small fires around Tok and Delta Junction. Because there were no lightning strikes preceding those fires, they are classified as being caused by humans. It remains unclear, however, how people caused those fires, officials said. Fires classified as human-caused can include escaped campfires, fires spread by discarded cigarettes, flames started by sparks from vehicles, machinery or equipment or other means. The state Division of Forestry is investigating the potential causes.