By Steve Quinn

JUNEAU, Alaska (Reuters) - Two fast-spreading Alaska wildfires have forced a series of evacuations, destroyed up to 45 homes and forced authorities to restrict traffic on a major highway connecting two of the state's largest cities, state officials said on Monday.

As many as 200 firefighters have been battling a 6,500-acre fire about 40 miles (64 km) north of Anchorage since Sunday afternoon.

About 137 miles (220km) south of Anchorage, crews are fighting a much smaller, but equally dangerous blaze that threatens nearly 200 homes.

Additional specially trained firefighting teams from the lower 48 states and Canada were scheduled to arrive on Monday night and begin assisting on Tuesday, Alaska Forestry Division spokesman Sam Harrel said.

Crews have been battling the fires on the ground and from the air, with help from the three Alaska National Guard Blackhawk helicopters, according to state reports.

Harrel said the larger fire was ignited by human activity but the specific cause is being investigated. Dry and warm weather accelerated the blaze, he said.

It started on Sunday afternoon near Willow, where the Iditarod, Alaska's famed sled-dog race, typically kicks off.

It initially covered about two acres, but within 11 hours had engulfed 6,500 acres, according to the forestry division.

Harrel said flames quickly jumped from one 30- to 40-foot spruce tree to the next, forcing a temporary closure of the Parks Highway, which links Anchorage in the state's south central region to Fairbanks in Alaska's eastern interior.

Residents along a 22-mile (35 km) stretch have been evacuated. The highway remains subject to intermittent closures and remained closed Monday night, Harrel said.

Governor Bill Walker had surveyed the area by air and issued a disaster declaration for the affected area.

By Monday morning, Harrel said, about 25 primary homes had been destroyed and as many as 20 secondary homes were also lost.

There are about 170 residential structures in the evacuation area, according to the Matanuska-Susitna Borough. These include year-round residences and seasonal cabins, said borough spokeswoman Patty Sullivan.

The borough also reported more than 200 people checking into evacuation centers, including residents and tourists, Sullivan said.

A second blaze, a 640-acre grass fire in the town of Sterling, began in the early afternoon, quickly destroying six structures and threatening 200 homes, Harrel said.

 

(Editing by Sandra Maler and Clarence Fernandez)