Residents of about 23 homes found out Monday afternoon that they can return to their homes Monday evening, as firefighters continue to gain the upper hand in a large wildfire burning in the foothills northwest of Fort Collins.

Authorities have determined that the 9,158-acre Picnic Rock Fire is no longer a threat to the evacuees in the Bonner Peaks subdivision along the Obenchain Road and South Greyrock Road. They can return at 8 p.m. but they will be entering the area at their own risk due to hazardous trees and other fire dangers, the Larimer County Sheriff's Office said.

Cooler, wetter weather has allowed firefighters to dig lines around 50 percent of the fire.

The 438 firefighters have about 10 more miles of line to dig to fully contain the blaze, which they are hoping to contain by April 7, authorities said.

One home and one garage have been destroyed.

One firefighter was transported to Poudre Valley Hospital by helicopter Sunday with minor head injuries, while another was taken by ambulance. Both were treated and released. Two other firefighters were taken off the fire lines Sunday after reporting dehydration and chest pains.

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Firefighters left the lines overnight to get some rest and returned Monday morning.

The majority of the residents in the Bonner Peaks subdivision were allowed back in their homes Saturday night. Judy and Bud Schalles were relieved to be home, but didn't know how much to unpack in case the fire shifts again.

"I don't want to be too optimistic and unpack everything," Judy Schalles said.

The fire started Wednesday afternoon when the fire from a trash burn raged out of control.

Three fire crews were transported to the west edge of the fire across Seaman Reservoir by pontoon boat on Sunday and airlifted back to the helibase in the evening. This operation will continue until firefighters can get a handle on the west side of the fire, authorities said.

Crews are focusing on the west side and the northern perimeter, which are areas that are closed to homeowners, and areas with hot spots and crowning activity.

With predicted weather, the fire could shift to a northern direction later if a dry weather pattern develops, authorities said.

The forecast calls for highs from 54-59 degrees with winds 5-10 mph from the southeast. Relative humidity is expected to be about 25 percent.

A spike camp was set up at the Livermore Community Center located about 13 miles north of Fort Collins on the Red Feather Lakes Road. A spike camp allows fire crews to be self-sufficient for several days and puts them closer to the fire line.

The Picnic Rock Fire is now twice the size of Big Elk Meadows and only 1,500 acres shy of Larimer County's largest fire -- the Bobcat Fire, which burned 10,665 acres. Before 2002, the largest fire in Larimer County history was around 2,500 acres at the beginning of the 20th century.

The cost of fighting the fire has amounted to $1.5 million.

Hewlett Gulch Trail and Grey Rock Trail remain closed.