Aidan Mattingly, Jack McElwee
For nearly two weeks this summer, Boise’s familiar blue skies were difficult to find.
A thick layer of wildfire smoke settled over the Treasure Valley in late July, hiding the foothills, reducing visibility and repeatedly pushing air quality into unhealthy territory.
“We had about a two-week period where the smoke was so thick you could smell it, almost taste it,” KTVB Chief Meteorologist Rachel Garceau said in an interview with The Arbiter. “[From] recent memory, this summer and the summer of 2024 were probably the worst.”
Although Boise State’s skyline returned to clearer skies just in time for the fall semester, the conditions behind this summer’s smoke have not completely disappeared.
Boise did not record a single day in the red, or unhealthy, air quality category in 2025, according to Garceau. In 2024, Boise spent 31 days in the unhealthy category and four days with very unhealthy air.
This summer brought another prolonged stretch of poor conditions.
National Weather Service Boise Warning Coordination meteorologist Jay Breidenbach said air quality climbed above an AQI of 200 during the worst stretch in late July, while visibility fell below a mile.
“It was almost like we were breathing in a chimney or something that day,” Breidenbach said. “Just the intensity of that event for two or three days was pretty extreme.”
The smoke came amid an active wildfire season nationwide. As of Aug. 26, nearly 51,300 wildfires had burned more than 7.9 millions acres, according to information the U.S. Wildland Fire Service provided to The Arbiter. Acres brought 65% above the 10-year average.
Many of the fires affecting Boise were burning hundreds of miles away.
The U.S. Wildland Fire Service identified several fires across Idaho and Oregon that contributed to Treasure Valley smoke with prevailing westerly winds pushing it directly toward Boise.
“All of those fires were west of us, and all of that smoke drifted right into the Treasure Valley,” Breidenbach said.
This summer’s weather conditions did not help lift the blanket of smoke over the Treasure Valley.
“Any wind we got really didn’t help with smoke transport or alleviation,” said Michael Toole, regional air shed coordinator for the Idaho Department of Environmental Quality. “It was just pumping down… and as active as those fires were… we were just basically downstream of them.”
Garceau said fine particles from wildfire smoke can rise into the atmosphere and travel hundreds of miles with stronger winds. Boise’s location makes the region particularly vulnerable to smoke from fires burning in Oregon.
Dry conditions also helped intensify the season.
Idaho’s snowpack sat 60% to 75% below normal as early as March, according to the U.S. Wildland Fire Service. The lack of moisture combined with drought leaves vegetation ready to burn earlier than usual.
Garceau said poor snowpack does not necessarily cause more fires to start, but it can create conditions that allow fires to spread more easily once they ignite.
“It can certainly cause drier conditions earlier in the season, which allows that vegetation to become kind of a tinderbox earlier than we’d like,” Garceau said.
September brought cooler temperatures, rain and higher humidity to the Treasure Valley, helping slow fire behavior.
The start of fall does not guarantee Boise has seen its last smoke of 2026. The U.S. Wildland Fire Service told The Arbiter Idaho’s wildfire season now lasts more than a month longer than it did in previous years.
Breidenbach said another stretch of dry weather could quickly change conditions.
“We’re not out of the woods yet,” Breidenbach said. “If we hit a stretch of dry weather, say in the second half of September, we could certainly see more wildfires, and fire produces smoke.”
Clearer skies offer students a welcome break from a summer marked by haze, but this summer demonstrated how the fires producing Boise’s next plume of smoke does not have to be anywhere near the Treasure Valley.
