Smoke from Boise County fires filtered into the Treasure Valley Wednesday morning - but that wasn't the only reason that the skies over the Valley were hazy.
Surface winds out of the northwest carried smoke from large fires in Oregon and Washington and upper-level winds brought smoke from a number of wildfires in Alberta, British Columbia and the Northwest Territories.
"That smoke is coming down with the jet stream," National Weather Service meteorologist Korri Anderson said.
During the night, smoke gets trapped with cooler air in the Valley. "It will be the worst in the mornings," Anderson said.
Michael Toole, regional airshed coordinator for the Idaho Department of Environmental Quality, expects similar conditions in the Valley on Thursday - and through next week. "We'll see some higher levels (of smoke) in the morning. As the summertime inversion breaks, we'll see some clearing," Toole said.
On Wednesday morning, visibility in Boise dropped to 5 miles at about 8:30 a.m. It began to improve around 10:30 a.m. but remained hazy.
The DEQ has issued a yellow air quality alert for the Treasure Valley on Thursday. Burning is banned in Ada and Canyon counties and all cities within.
Three large fires east of Garden Valley - part of the Whiskey Complex - have burned about 1,600 acres since they were ignited by lightning Sunday night. The smoke has created unhealthy air conditions in Garden Valley and Idaho City, according to the DEQ.
The DEQ's real-time air quality map online Wednesday showed Idaho City and Garden Valley at red alert levels. The values from the monitors are one-hour averages, so they fluctuate during the day, Toole said.
Idaho City's Air Quality Index number hit 190 Wednesday morning. AQIs between 151 and 200 are in the red category, defined as unhealthy for everyone - not just sensitive groups. By the afternoon, the air quality had improved somewhat.
The smoke was even worse in Garden Valley on Tuesday, when an AQI number of 212 was registered. That's in the purple, or very unhealthy, range. That occurred between 11 a.m. and noon.
FOREST LAND CLOSED BY BOISE COUNTY FIRES
No structures have been lost in the Whiskey Complex fires, but Boise National Forest officials announced an area closure around the three fires Wednesday, extending to near Placerville, Centerville and Pioneerville.
The Hot Springs Campground east of Garden Valley along Banks to Lowman Highway also is closed.
"The rationale for the closure (and restricting) public access is to ensure we know who is in there, how long they need to stay and what the current or forecasted fire danger is," Boise National Forest spokesman Dave Olson said. The Forest Service has authority to close forest roads; the sheriff decides on county roads, Olson said.
Conditions are smoky, but Banks to Lowman Highway remains open.
Voluntary evacuation orders remain in effect for South Fork Payette River Road (60 homes) and the Pioneerville area (10 homes).
Community meetings are planned for 6 p.m. Thursday at Garden Valley High School and 6 p.m. at the Centerville Community Center. Public updates are planned at 2:30 p.m. daily on Garden Mountain Radio (gardenmountainradio.com).
Katy Moeller: 377-6413