Visibility fell to below 2 miles at the Boise Airport at about 4 p.m. Sunday, according to the National Weather Service. Typical visibility on summer day is at least 10 miles, and it's not uncommon for it to be 50 miles.
The air quality may get worse before it gets better, a meteorologist said.
Monday morning may be very smoky, with very low visibility due to inversion conditions that trap pollutants near the ground with cooler air.
Wind conditions Sunday were very light, just 5 miles per hour. Forecasters say there's a chance that northwest winds on Tuesday could help clear out some of the smoke.
The high temperature Sunday in Boise was 96. The high on Monday is expected to be about 99, and the rest of the week will be in the mid-90s.
At about 1:20 p.m. Sunday, the Idaho Department of Environmental Quality issued an updated air quality alert for the Treasure Valley, warning the public about deteriorating air quality. An orange air quality alert was issued for Sunday and Monday due to smoke from wildfires in the region and beyond.
Under an orange alert, people who are sensitive may have respiratory symptoms. People with lung disease, children, older adults, and people who are active outdoors are the groups most at risk. Officials urge these individuals to consider postponing strenuous activities until air quality improves.
The public is asked to help reduce air pollution by limiting driving, combining errand trips, avoiding woodstove and fireplace use and not burning outdoors.
About a half dozen major wildfires are burning in Southwest and Central Idaho. Here is the latest information as of Sunday afternoon:
Location: Between Banks and Garden Valley
Size: 5,140 acres, 25 percent contained
Closures: Idaho 55 and the Banks-to-Lowman Road are open. Expect heavy fire traffic and rolling rocks that could fall without warning. There have been reports of people stopping to take pictures and walk into the fire area. Travelers are asked to not stop within the fire area on either road because of several hazards in the area and the safety hazard that parked vehicles cause to the public, firefighters and fire operations. The Payette and South Fork Payette rivers are open, but rafters should use caution where helicopters are dipping and be cautious of trees weakened by fire falling into the river.
Evacuations: No evacuations are currently in place, but residents to the north and east of the fire are asked to remain vigilant. Several agencies are collaborating on comprehensive evacuation plans, in the event that it is necessary.
Location: Northwest of Stanley in the Cape Horn area
Size: 49,322 acres, 3 percent contained
Closures: A pilot car is guiding traffic on Idaho 21 between Grandjean Road and Bear Valley Road, about 21 to 25 miles south of the Stanley area. The road has been closed since Thursday afternoon. All forest roads and trails in the Cape Horn, Seafoam and east of the Middle Fork Salmon areas are closed including the following campgrounds: Beaver Creek Campground, Lola Creek Campground, Marsh Creek Transfer, Josephus Lake.
TRINITY RIDGE FIRE
Location: Atlanta, Rocky Bar and Middle Fork Boise River areas
Size: 32,250 acres, 5 percent contained
Closures: The Pine-to-Featherville Road is open to residents only. All forest roads and trails in the area roughly between Featherville and Idaho City north to near Lowman and Grandjean are closed.
Structures destroyed: Three to four commercial structures and four outbuildings/other structures at the Dutch Creek Guard Station.
Evacuations: Elmore County Sheriff's Office and local EMS are coordinating for possible evacuations.
MUSTANG COMPLEX FIRE
Location: North of the Salmon River between the Corn Creek and Shoup areas.
Size: 6,654 acres
Closures: Motorists should stop at the North Fork Ranger Station for instructions about travel along the Salmon River Road. If a closure order is implemented, a checkpoint will be established at Cove Creek. The following forest roads are closed: Colson Creek Road (123) from the junction with Salmon River Road to the junction with Spring Creek Road (38), Long Tom Road (166), Corn Lake Road (64) and Cayuse Point Road (67). Horse Creek Road (65), Horse Creek Campground and Horse Creek Hot Springs also are closed.
Community meeting: 3 p.m. Sunday at the North Fork Fire Department.
CAVE CANYON FIRE
Location: Southwest of Burley, west of Oakley.
Size: 80,012 acres, 57 percent contained
Closures: Evacuations are in effect for Rock Creek Canyon and Dry Creek roads.
STAGE 1 FIRE RESTRICTIONS
Continued hot, dry conditions throughout southwest and central Idaho have prompted Stage 1 fire restrictions on an expanded slate of private and government land throughout much of southwest and central Idaho Areas under Stage 1 Fire Restrictions now include:
All private, state and BLM protected lands outside incorporated city limits within Ada, Boise, Canyon, Elmore, Gem, Owyhee, Payette, Washington counties, and portions of Idaho, Adams, Valley, Custer, Elmore, Camas and Blaine counties;
All Boise National Forest lands within Boise, Elmore, Gem and Ada counties, and a portion of Valley County;
All Payette National Forest lands within Adams, Washington and Idaho counties, and a portion of Valley County; and
All Sawtooth National Forest lands within Elmore and Camas counties, and portions of Blaine and Custer counties
Stage 1 fire restrictions prohibit the following acts:
Using a fire, campfire or stove fire, except within a designated recreation site, or on the user's own land within an owner-provided structure.
Smoking, except within an enclosed vehicle, building or designated recreation site, or while stopped in an area at least three feet in diameter that is barren or cleared of all flammable materials.