(Adds details from wildfires in Arizona, Nevada and California)
By Yereth Rosen
ANCHORAGE, July 8 (Reuters) - About 600 people and several sled dogs were evacuated as a massive wildfire in Alaska marched toward homes in communities northeast of Fairbanks, fire officials said on Monday.
Heavy plumes of black smoke hampered the ability of firefighters to deploy water-dropping aircraft or make much progress in containing the flames, which spread north and northwest to threaten 750 homes and about 150 other structures.
Whipped by strong winds, the so-called Stuart Creek 2 fire grew by 25 percent this weekend and blackened 100 square miles (259 sq km) as of Monday morning, said InciWeb, the inter-agency fire information website run by the U.S. Forest Service.
It was one of dozens of wildfires burning across the United States, including a major blaze raging in the mountains northwest of Las Vegas. Experts say the current fire season could be one of the worst on record.
In Arizona, the remaining evacuees from the deadly Yarnell Hill fire, which killed 19 members of an elite Hot Shots crew on June 30, were allowed to return home on Monday. The lightning-sparked blaze has blackened some 8,400 acres of rugged, brush-covered hillsides and ravines since June 28 and was said to be 90 percent under control on Monday.
A memorial service for the 19 firefighters was to be held on Tuesday at an arena in Prescott Valley. Vice President Joe Biden is expected to attend.
SLED DOGS EVACUATED
In Alaska, officials have issued evacuation orders for 600 residents, and as of Sunday 200 to 300 people had confirmed that they had left, fire information officer Rich Phelps said.
But he said it was hard to determine how many people had evacuated. Some homes in the area are not occupied year-round. A shelter was set up at an elementary school, and a few people had taken refuge there, he said.
"You can't tell people they have to leave," Phelps said. "Some leave, and some don't."
Nearly 700 firefighters were working to try to control the blaze, which was only 5 percent contained as of Monday afternoon. It is the most serious of the more than 90 wildfires actively burning in Alaska, Phelps said. Officials said the blaze was ignited on June 19 by a military exercise.
The affected area, with the unincorporated communities of Two Rivers and Pleasant Valley, is home to several top-ranked sled-dog racers. Rick Swenson, a five-time champion of the Iditarod Trail Sled Dog Race, lives in Two Rivers, as does Aliy Zirkle, the runner-up in the past two races.
Many of the dogs, along with horses and other domestic animals, have been taken to the Tanana Valley Fairgrounds in Fairbanks, Phelps said.
Hot and dry weather has fueled a busy fire season this year in Alaska. So far, 442 wildfires have burned more than 1 million acres, including 92 fires believed to be active as of Monday.
In Nevada, a blaze burning 35 miles northwest of Las Vegas has become the nation's top-priority fire, according to federal officials, and the U.S. Federal Emergency Management Agency on Monday committed funds to help put it out.
The Carpenter 1 fire, as it is known, was entering its second week and has prompted the evacuation of about 500 people with homes in the Spring Mountain Recreational Area. Started by lightning on July 1, it has charred some 15,000 acres and is only 15 percent contained, Bureau of Land Management spokeswoman Madonna Lengerich said.
And in California, authorities ordered new evacuations because of the Chariot fire, which started southeast of Julian in the Cleveland National Forest around noon on Saturday. Four firefighters have been treated for minor injuries while battling the blaze, officials said. (Additional reporting by Tim Pratt in Las Vegas, Tim Gaynor in Arizona, Marty Graham in San Diego and Dan Whitcomb in Los Angeles; Writing by Dan Whitcomb; Editing by Dina Kyriakidou and Leslie Adler)