The Treasure Valley is socked in with smoke due to the Walker Fire’s location and diurnal mountain winds — winds that blow uphill during the day and downhill at night. Compounding the problem is a high pressure system trapping cooler air and smoke in the Valley at night, explained Jeanne Allen, a meteorologist with the National Weather Service office in Boise.
Allen said she expects the weather pattern to hold through the end of the week, with a slight chance of rain over the weekend.
On the Department of Environmental Quality’s six-color scale of best to worst air quality — green, yellow, orange, red, purple and maroon — the Treasure Valley has been under a red alert since Monday.
When the air quality index is between 151 and 200 — a red alert — everyone might begin to experience some adverse health effects, and members of the sensitive groups could experience more serious effects, according to DEQ. Wednesday’s air quality forecast is 170.
Symptoms of wildfire smoke sensitivity include shortness of breath, chest pain or tightness, headaches, coughing, irritated sinuses, stinging eyes, sore throat and fatigue, according to the Idaho Department of Health and Welfare.
Smoke could worsen symptoms for people who have respiratory conditions, such as allergies, asthma and chronic obstructive pulmonary disease.
Older adults are more likely to be affected by smoke because they are more likely to have heart or lung problems.
Children, too, are more likely to be affected by health threats from smoke because their airways are still developing and because they breathe more air per pound of body weight than adults. Children also are more likely to be active outdoors.
Boise and West Ada school districts on Monday and Tuesday canceled or moved indoors all athletic events, activities and practices.
DEQ recommends all individuals consider postponing strenuous activities until air quality improves; limiting driving or combining trips and errands; and not burning outdoors.
Firefighters battling the blaze near Idaho City on Tuesday kept flames from creeping closer to Idaho 21 and homes on its southern flank.
The fire started Saturday afternoon about 8 miles southwest of Idaho City in Boise County. Due to high winds on Saturday, the fire quickly spread from approximately 65 acres to 2,500 acres overnight, burning three cabins and one outbuilding. On Monday and Tuesday the fire spread to the northwest into the more heavily timbered Wild Horse and Rattlesnake creeks areas.
Road and forest closures are in effect on the west side of Idaho 21 between the Grimes Creek and Centerville areas.
Residents in the Macks Creek, Wolf Creek and Pine Creek areas are under an evacuation order.
The fire’s cause is still under investigation.