(Adds Obama comments, paragraphs 6-9)
By Victoria Cavaliere
SEATTLE, July 22 (Reuters) - Firefighters gained ground on Tuesday against the largest wildfire in Washington state's history but the massive blaze that has destroyed 200 homes continued to threaten some communities and forced a fresh round of evacuations.
The Carlton Complex fire burning east of the Cascade Mountains and 120 miles (190 km) northeast of Seattle, was 16 percent contained on Tuesday, more than a week after it was sparked by lightning, officials said.
The massive blaze charred 243,000 acres, or 380 square miles (980 square km), the largest fire in the state's history, according to Larry Weaver, a spokesman for agencies working to contain the blaze.
"There's increased progress," Weaver said. "We are very cognizant of weather changes, and the fire is still a dangerous active fire."
About 18 wildfires are currently burning across the Pacific Northwest, many triggered by lightning and expanding rapidly amid dry conditions in parts of California, Oregon, Washington and Idaho.
President Barack Obama, who came to Seattle on a fundraising trip, offered the support of the U.S. government to help support those affected by the blazes.
"Obviously these are very difficult fires," Obama said at his first fundraiser of the evening. He said the federal government was authorizing an emergency declaration on electrical power for the affected areas.
Obama said drought, changing precipitation patterns, and climate change were fueling more and more forest fires every year.
"The trend lines indicate the potential for increased forest fires. We've seen the budget for forest fires jump at an extraordinary pace over the last several years, so much so that we're going to have to call on Congress to change how we fund forest fires," he said.
The Carlton Complex fire has been a special concern to emergency officials because of its proximity to towns and cities in Washington's Methow Valley, home to about 10,000 people.
More than 2,000 firefighters, backed by air support, were building containment lines, aided by dropping temperatures and low wind. Rain is forecast for Wednesday, but the lightning it could bring raised concerns.
Even as evacuation notices were downgraded or dropped in some areas, new recommendations were put into place late on Monday for about 100 residents in the community of Carlton.
Residents of rural areas including Pleasant Valley and Leader Lake, Alpine Lake, and White Rock Road were also urged to leave.
Emergency crews, which were continuing to assess damage, said about 200 homes had been lost. More than 1,200 homes and dwellings were evacuated at the height of the blaze.
The fire was also blamed for one fatality, a 67-year-old man who died on Saturday while trying to protect his home.
Dozens of power lines were destroyed across the region, leaving electricity and communication inconsistent or down in some areas, according to the Okanogan County Sheriff's Office.
The Carlton blaze was still smaller than the Buzzard Complex fire raging in neighboring Oregon. At 395,000 acres (160,000 hectares) and 85 percent containment, that fire was still considered extremely dangerous and had caused smoke conditions in rural communities hours away, according the Bureau of Land Management. (Additional reporting by Jeff Mason; Editing by Eric Beech and Eric Walsh)