A helicopter delivering water to firefighters battling a blaze in the Klamath National Forest crashed Monday, killing the pilot, authorities said.

Investigators were trying to determine what caused the chopper to go down in "extremely rugged" mountain territory about 12 miles southeast of Happy Camp in Siskiyou County, said Duane Lyon, a U.S. Forest Service spokesman.

The pilot, who was not identified, was under contract with the Forest Service but was not a government employee, Lyon said. The pilot was the only person on board.

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The helicopter was carrying a large water container to refill hand-pump backpacks for firefighters on the ground. Some firefighters saw the helicopter crash and reported it to emergency dispatchers.

More than 1,100 fire crews were battling the cluster of about 30 lightning-sparked fires covering 14 square miles near the Oregon state line. The fires, which started July 10, had threatened up to 550 homes near the town of Happy Camp, but none has been destroyed.

Fire crews wrestled with dozens of huge wildfires across the West on Monday in Idaho, Nevada, Oregon and Utah, the National Interagency Fire Center said.

Fire managers were worried that dry lightning storms in some of those states could spark further blazes, though the systems were expected to bring rain Tuesday, the agency said.

"It's great to have rain, but there's always the possibility of a downdraft and erratic winds. There's a high concern over additional lightning strikes," said Ricardo Zuniga, a fire information officer in Utah, where a more than 33-square-mile blaze has forced the evacuation of several communities.

There already was enough wind to carry smoke 90 miles north to Salt Lake City, fire information officer Michelle Fidler said.

The fire started Thursday and remained about 15 percent contained, Fidler said.

The small towns of Oaker Hills, Indian Ridge, Elk Ridge, Indianola and Holiday Oaks were evacuated, officials said. A shelter was set up at a school in Mount Pleasant, Zuniga said.

In southwestern Utah, a fire in and around Zion National Park was 40 percent contained after burning 14 square miles.

No buildings had burned, but an evacuation order remained in place until Tuesday for about 800 homes, said Deanna Younger, a fire information officer. Most were unoccupied seasonal homes, and only about 50 people evacuated, she said.

Mandatory evacuation orders remained in effect for the tiny town of Jarbidge, Nev., where an 887-square-mile fire on the Idaho-Nevada line was burning within a mile, fire information officer Bill Watt said. While roughly 90 percent of the fire was in Idaho, the most active part was in Nevada and was 15 percent contained, he said.

"Crews have set up sprinkler systems and hoses to protect homes and buildings in Jarbidge," Watt said. "We're hopeful of keeping the fire out of Jarbidge."

An evacuation order for Murphy Hot Springs was lifted for residents only. A lot of grazing land burned, and cattle likely died in the fast-moving blaze, fire spokeswoman Pam Bierce said.

A wildfire in southern Idaho had covered more than 880 square miles, growing by about 200 square miles in just 24 hours during the weekend. Fire officials said it threatened tracking and radar facilities at Mountain Home Air Force bombing and firing range, which is used by pilots training for duty in Iraq and Afghanistan.

In Montana, a nearly 14-square-mile fire burning on the edge of Lewis and Clark National Forest prompted an evacuation order for 40 summer homes. Many were unoccupied, said Lewis and Clark County Sheriff Cheryl Liedle.

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