By Timothy Pratt
LAS VEGAS (Reuters) - Clouds, cooler air and summer rain have helped firefighters gain ground against a wildfire in mountains outside Las Vegas, officials said on Friday.
The blaze, sparked by lightning on July 1, has charred more than 28,000 acres of pinyon-juniper woodlands popular as an outdoor getaway by residents of Nevada's biggest metropolitan area.
Firefighters were able to build containment lines around more than 40 percent of the fire's perimeter after up to a half inch of rain fell through parts of Kyle Canyon on Thursday and cloud cover brought cooler weather.
"It was a much better day," said Suzanne Shelp, spokeswoman for the U.S. Forest Service's fire incident management team, adding that temperatures were expected to remain cooler on Friday, at around 75 degrees Fahrenheit.
"We're not expecting much more help from rain," Shelp added.
The Carpenter 1 blaze raging in the Spring Mountains National Recreation Area was one of more than a dozen burning across the United States. Experts say this could be one of the worst U.S. fire seasons on record.
In recent weeks, a Colorado wildfire ranked as that state's most destructive on record ravaged more than 500 homes and killed two people. In Arizona, 19 members of an elite "hotshots" crew died while battling a separate fire on June 30.
In Nevada, 12 "hotshot" U.S. fire crews have been called to battle the fire, which the National Interagency Fire Center in Idaho has considered for several days the top priority fire in the nation.
Firefighting efforts have cost nearly $12 million to date, Shelp said. The blaze at times has sent plumes of smoke over the greater Las Vegas metropolitan area. Six buildings, including at least one commercial structure, were destroyed on Tuesday, officials said.
Northern Nevada has lost about 25,000 acres to another fire sparked by lightning on July 4 in Douglas County. That fire was also about 40 percent contained as of Friday.
(Editing by Cynthia Johnston; Editing by David Gregorio)