LIVERMORE, Colo. — Warm, dry weather hindered hundreds of firefighters Friday as they battled a blaze in northern Colorado that federal officials say started with a camp stove.

More than a dozen homes remain under evacuation orders as the fire has grown to cover about 12 square miles. Officials hope to be able to allow evacuated residents to return home soon.

Firefighters protected neighborhoods by burning grass, shrubs and small brush near homes to prevent the wildfire from advancing that direction. Firefighters got a boost as wind pushed the blaze to an area scorched by a previous wildfire, which helped slow its growth.

Still, the fire about 20 miles northwest of Fort Collins is blazing mostly unchecked. Two planes and five helicopters were on hand to help fight the blaze. No homes or buildings have been damaged. Three firefighters suffered minor injuries fighting the blaze.

The U.S. Attorney's Office said Friday that James J. Weber of Fort Collins started the fire with an outdoor stove while camping in the Roosevelt National Forest earlier this week.

U.S. Forest Service investigators say the 56-year-old Weber, a mental health counselor at Colorado State University, tried to stamp out the fire Monday but then fled as the blaze spread and later reported starting the fire to the Larimer County Sheriff's Office. There is no cell phone service in the area where the fire started.

The Forest Service issued Weber a citation for causing a fire without a permit. He faces a $300 fine. However, the authorities also plan to pursue restitution for the blaze.

Weber's lawyer, Joseph A. Gavaldon, said that his client is praying with "hope that this gets under control."

Weber "is most concerned about what's going on now," Gavaldon said, adding that Weber is focused on the well-being of the firefighters, residents and wildlife in the area.

Gavaldon refused to comment on how the fire started or any events that followed.

The Colorado blaze was one of several burning in the West. Wildfires charred terrain in Arizona, California, Nevada, New Mexico and Utah.

The most significant blaze in Arizona has led to the evacuation of two communities in the northern part of the state, including a historic mining town about 85 miles north of Phoenix. The blaze has grown to nearly 16 square miles and has destroyed three homes and a trailer. No significant injuries have been reported.

More than 600 firefighters supported by water-dropping helicopters are fighting the blaze.

Warm, dry weather and mountain wind have made the fire difficult to contain. But National Weather Service officials say the gusts are expected to die down considerably over the weekend, which should help fire crews make substantial progress.

Investigators say the fire started in a home on Sunday.

Other fires dotted Arizona but did not threaten any structures, authorities said.

In California, a blaze that started across the U.S.-Mexico border advanced into San Diego County, where it burned about 150 acres of brush. Crews expected to have the fire contained late Friday. No homes were threatened. No significant injuries were reported, and the cause of the blaze was under investigation.

In Nevada, a blaze grew to 27 square miles and threatened sage grouse and mule deer habitat. No homes were in danger, and no injuries were reported. The cause of the blaze was under investigation.

In New Mexico, firefighters battled a 410-acre blaze in Gila National Forest in the southwest part of the state. No structures were at risk, and no injuries were reported. Officials say lightning sparked the blaze Wednesday.

In Utah, rain and cooler temperatures helped slow a wildfire that burned nearly 2 square miles in the western part of the state. Firefighters hoped to contain the blaze by late Friday. No structures were threatened, and no injuries were reported. Authorities say the blaze was sparked yesterday by heat from a passing car.

In Colorado, Gov. John Hickenlooper declared a disaster, allowing $3 million of the state's emergency fund to be spent fighting the fire.

The blaze is charring a drought-stricken area of steep, rocky terrain scattered with dry ponderosa pine trees, grass and shrubs.

It was approaching the city of Greeley's water reservoir, but officials said the supply hasn't been affected.

The area has seen several large fires in the past 12 years. A fire started by an abandoned campfire in 2000 scorched more than 16 square miles and destroyed 22 buildings.

A 2004 blaze started by a couple burning trash scorched nearly 14 square miles, destroying a home.