Alaska wildfire officials are reviewing their initial assessment of the cause of a weekend fire that burned at least 50 structures along the Parks Highway.
The McKinley fire began Saturday in high wind and was initially attributed to a tree toppling onto a power line.
The cause of the fire is now under investigation, Tim Mowry, spokesman for the Alaska Division of Forestry, said Tuesday. The fire covers 4.7 square miles. The number of people displaced by the fire and the number of homes burned have not been tallied, he said, as firefighters continue working to suppress the fire.
Southwest of the McKinley fire, a second fire broke out Saturday near the Nancy Lake Recreation Area and covered nearly 3 square miles. It was believed to be human caused, Mowry said, because no lightning strikes were recorded. The growth of both fires declined Monday when winds diminished.
"The wind was a big thing," Mowry said. "That's the biggest driver of both of those fires."
More than 150 personnel were assigned to the fires, and more were on the way. A dozen engines from Fairbanks were scheduled to arrive Tuesday to fight the roadside fires.
"Engines can do a great deal of good, both for structure protection and for suppression," Mowry said.
Five wildfire crews with 100 firefighters from California landed Monday in Alaska to help with suppression efforts. Another 300 firefighters from western states were scheduled to arrive Tuesday through Thursday, Mowry said.
Smoke from the fires north and south of Anchorage continued to pour into the city.
Haze obscured the Chugach Mountains, which normally provide a stunning backdrop to the cityscape. Some pedestrians wore bandanas or masks.
The city's sole air monitoring station recorded 121 micrograms of fine particle pollution between 9 and 10 a.m. Tuesday, said Matthew Stichick, a municipal air quality specialist. That level carries a warning for people with heart or lung disease, the elderly and children to reduce prolonged or heavy exertion.
Conditions were forecast to improve by evening.
"I'm expecting some more impacts Wednesday morning and then some improvement," Stichick said.
Tuesday was the first day of school in Anchorage. Principals and coaches had the discretion of holding recesses inside because of the conditions as the Anchorage School District canceled all outdoor athletic practices and competitions.