The National Weather Service has issued an air quality alert—in effect until 11:30 a.m. Friday—due to degraded air quality from traveling wildfire smoke.
The alert closely followed a Thursday morning health caution issued by the Idaho Department of Environmental Quality for Blaine County and seven other surrounding counties.
By Thursday afternoon, Ketchum’s Air Quality Index (AQI) read 154, or “unhealthy” for all people regardless of present health condition. That reading came from the department’s monitoring station at Ketchum’s Ernest Hemingway STEAM School and reflected more than three times the amount of particulate that was in the air Wednesday evening.
At a reading of 154, the air could be harmful to anyone, but poses particular risk to “sensitive groups,” including the elderly, children and those with heart or lung conditions. All people are advised to limit prolonged exertion and reduce time spent outdoors.
Idaho DEQ spokesman Bobby Dye said the smoke in Blaine County has traveled from California and combined with wildfire smoke in Oregon, Nevada and Idaho.
“DEQ staff are carefully observing particulate matter concentrations,” he said.
A new wildfire near Elk City and the Bear Creek Fire just over the border in Montana may also be contributing to the smoke in the Wood River Valley, according to a Thursday morning forecast from DEQ Smoke Analyst Sally Hunter.
“Regional smoke from fires in the west that is trapped within this high-pressure flow will continue to circulate clockwise around the western United States,” Hunter stated. “Smoke will move up and down within the boundary layer.
“Expect to see higher readings of pollution during the nighttime and early morning hours before improving in the afternoon.”
Hunter said some of the smoke coming from the southwest may subside later this week, but the valley will continue to receive smoke from the west and northwest.
The Idaho DEQ also instated a voluntary burn ban for residential wood-burning activities, such as grilling, on Thursday.