NEAR IDAHO CITY (KBOI and AP) - A wildfire in the Boise National Forest was threatening about 100 homes in remote Boise County Wednesday.
Authorities say three fires of unknown origin merged into one big blaze.
Boise County Sheriff Ben Roeber issued a voluntary evacuation notice for homes that are within 1 mile of the fire perimeter due to the concerns with potential increased fire activity due to potential weather impacts.
He is also concerned with the layout of the subdivision with its narrow roads and lack of safety zones for firefighters.
But authorities say crews are making good progress. Officials say the fire is 45 percent contained and that full containment is expected Friday by 6 p.m.
The Avelene Fire on about 250 acres is a concern for the Clear Creek Subdivision, a scattered outpost of rural houses near the Junction of State Highway 21 and Grimes Creek Road in Boise County, about 25 miles from Boise, according to the Boise National Forest.
"No structures have been lost, and two Hotshot crews are prepping the area this morning for defense of 20 homes," forest spokesman David Olson said.
There have been "no evacuations yet, but according to the Boise County emergency management coordinator, they are being planned," he said.
Hand crews, engines, helicopters and air tankers were battling the blaze.
Two additional small blazes were reported burning in the foothills just northeast of Boise near a populated area, likely started by storms that rolled through the area Wednesday morning and brought lightning and thunder but little rain. | Photos from the Scene
Bureau of Land Management crews were investigating.
The estimated 100-acre "C'' Fire, about 10 miles east of Donnelly in Valley County, to Boise's north, received additional firefighting resources late Tuesday. About 80 firefighters are responding to the blaze, along with a heavy lift helicopter.
Officials say lightning has sparked several new wildfires across Idaho.
In the BLM's Twin Falls District, lightning storms caused three new fires Tuesday.
BLM officials say one of the new fires near the Idaho-Nevada border has already burned 3 square miles and forced the closure of a stretch of U.S. Highway 93. Fire officials expected to have the fire contained late Tuesday.
Officials also are monitoring nine fires in southwestern Idaho that range in size from a tenth of an acre to more than 3 square miles. At least two were human-caused.
BLM officials say they expect full containment of the Kinyon Road Fire on Wednesday.
It has been the state's largest fire to date in 2012, burning through some 340 square miles of grass and sagebrush in south-central Idaho over the past three days.