Thousands of families in Utah have been evacuated from their homes as winds continue to fuel a wildfire believe to have been sparked by target shooters.

Residents of at least 2,300 properties in the northern part of the the state sought refuge Friday, as flames scorched a growing area around 40 miles south of Salt Lake City.

High winds that have helped fan the blaze onto tinder-dry grasslands are expected to last throughout the weekend, prompting fears of further upheaval for some people in areas of risk.

The fire began to take hold on Thursday.

Authorities were initially worried as flames moved toward property owned by an explosives company, but the focus turned yesterday to saving homes as winds kicked up and the fire moved toward Saratoga Springs.

On Friday, fire officials were calling in additional aircraft and extra ground crews.

Utah County Sheriff Jim Tracy said he feared the fire could take down the area's power grid, shutting off electricity to up to 7,000 homes.

"Several power poles and transformers ... up and down the fire lines have burned," Tracy said Friday evening. "If the fire gets a couple more critical poles and drops that grid, wires down on the ground, it will black out this entire area."

Bureau of Land Management (BLM) spokeswoman Teresa Rigby said the 2,300 houses evacuated include residents who voluntarily left, along with those ordered to leave.

BLM officials say they believe the blaze was caused when a bullet hit a rock and sparked the fire. This is the 20th target-shooting related fire this year in Utah, they said.

One firefighter had suffered minor burns, and no structural damage had been reported, said Jason Curry, a spokesman for the Utah Division of Forestry, Fire and State Lands.

A continued mix of hot, windy and extremely dry conditions has raised the fire danger across Utah and parts of Wyoming, Arizona, Nevada and Colorado.

At a wildfire burning on more than 69,000 acres in northern Colorado, some homes were being evacuated because of several spot fires started by winds outside the main fire. Some of those residents were evacuated after the fire flared up on Sunday and had only returned home Wednesday.

The mix of conditions that makes it easy for new fires to start and spread and cause existing fires to flare up is expected to last through Saturday.

The fire west of Fort Collins has now destroyed at least 191 homes. It's also blamed for the death of a woman found dead at her ranch.

In southern Colorado, a new 300-acre fire near Mancos was threatening at least 10 structures and prompted officials to evacuate some homes east of town, federal officials said.

Gov John Hickenlooper's office said he signed executive orders releasing $6.2 million more in state disaster money to fight the fire and two others.

The northern Colorado fire will have $5 million more available, on top of $20 million made available by a previous order. The fire has qualified for 75 percent federal reimbursement for firefighting costs, Hickenlooper's office said.

A fire near Lake George will get $1 million, and the Stuart Hole fire in Larimer County will receive $200,000. The disaster money is coming partly from reserve funds.