By Steve Quinn and Courtney Sherwood
JUNEAU, Alaska/PORTLAND, Ore. (Reuters) - Firefighters in Alaska, Oregon and drought-hit California fought on Monday against several massive wildfires that have blackened swathes of overheated U.S. West Coast states, even as crews brace for warmer temperatures later this week, officials said.
Aided by falling temperatures, Alaska firefighters have gained an edge over two major blazes in the greater Anchorage area that have destroyed dozens of homes, though some residents were being allowed to return to their homes.
Firefighters have contained about 25 percent of a 7,300-acre (2,954-hectare) blaze in Sterling, about 140 miles (225 km) south of Anchorage, and nearly 80 percent of a blaze in Willow, the start site of the famed Iditarod dog sled race.
Even with the cooler temperatures, National Weather Service officials say lightning strikes combined with dry conditions still make many areas of Alaska vulnerable to rapidly spreading fires, as authorities battle nearly 150 active blazes.
The fire-ripe conditions extended down the U.S. West Coast from Oregon to California, where lower temperatures briefly allowed firefighters to gain a toehold on several major blazes even as forecasts called for another heat wave amid a historic drought, said Cal Fire spokesman Daniel Berlant.
"This year in total we've seen a significant increase in fire activity in California due to the drought," Berlant said.
Daytime temperatures reached a slightly cooler 82 degrees Fahrenheit (28 C) in a mountainous national forest outside Los Angeles, helping the more than 1,900 firefighters expand containment lines to around 21 percent of a fire that has charred some 17,305 acres (7,003 hectares), the San Bernardino County Fire Department said.
Campsites, hiking trails and a highway remained closed and some 500 structures were threatened, as crews dug containment lines and readied fire engines and bulldozers near the community of Pioneertown, about 8 miles (13 km) from the fire's edge, which was so far not threatened.
Outside of Fresno, a roughly 920-acre (372-hectare) fire has destroyed three structures and prompted a mandatory evacuation of nearby communities and was about 75 percent contained, Cal Fire reported.
Another fire near San Luis Obispo destroyed two homes and multiple outbuildings, though an evacuation order had been lifted.
In Oregon, firefighters were bracing for significantly warmer temperatures and drier air later in the week as they made progress against the roughly 4,800-acre (1,943-hectare) Buckskin Fire that was 30 percent contained, incident commander Doug Johnson said.
Though no property is threatened, some public forest lands have been closed.
(Reporting by Courtney Sherwood in Portland, Oregon and Steve Quinn in Juneau, Alasak; Additional reporting by Eric M. Johnson in Seattle; Editing by Eric Walsh)