Smoke forecast
Where the smoke over Boise was, and where the model sends it next. Scrub back 12 hours or forward 48. Every hour shown is a model estimate, not a measurement.
The scale is anchored to visibility, because that is the one reading you can take yourself without trusting a model. Distances are approximate.
Shafer Butte reads clean above Bogus Basin, about sixteen miles north, and the Owyhees hold the far southwest horizon.
Shafer Butte has flattened to a blue shape and the Owyhees are gone, though the Boise Front still shows its ridgelines.
The foothills reduce to a silhouette. Table Rock, about three miles east of downtown, is the furthest thing with texture.
From the Greenbelt the downtown towers hold about a mile off, while the foothills behind them vanish entirely.
The top of the Zions Bank building goes. From the Boise River you lose downtown.
Boise is surrounded by fire country and sits in a valley that holds what arrives. Smoke comes from central Idaho, eastern Oregon, Nevada, and on bad years from California and the Pacific Northwest, riding southwesterly and westerly flow into the Treasure Valley. The valley's own geometry does the rest, trapping smoke against the foothills for days after the flow shifts.
The 2020 and 2021 seasons both put Boise into extended stretches of unhealthy air, and the Treasure Valley has repeatedly recorded some of the worst readings in the country during peak weeks.
The verdict at the top of this page answers that for Boise specifically, reading the model over the Treasure Valley floor. That is the number worth having, because the valley traps smoke against the foothills, so the air along the Greenbelt can be meaningfully worse than the air a few hundred feet up the Boise Front on the same afternoon. Everything shown is a model estimate rather than a measurement at your address.
That is the headline answer above: the clear time, the first stretch of at least six straight hours below the Hazy threshold. The Treasure Valley’s geometry is the reason it can lag. Smoke gets held against the foothills for days after the flow that delivered it has shifted, so the clear time here is a forecast about the valley emptying rather than about the wind turning.
Central Idaho, eastern Oregon, and Nevada are the near sources, with California and the Pacific Northwest adding to it in bad years on southwesterly and westerly flow. But the Treasure Valley is half the answer on any given day, because it holds what it is given, which is how this valley has repeatedly recorded some of the worst readings in the country during peak weeks without being the closest place to a fire.
Central Idaho and eastern Oregon most often, Nevada and the Great Basin on southerly setups, and California and the Pacific Northwest on the bad years. Reno is the upwind check on the Great Basin and northern Sierra case, sitting on the same southwesterly flow a step earlier. Run the timeline backward on the map and the approach direction sorts the near sources from the far ones.
The five-day strip above gives the day-by-day read and the timeline covers forty-eight hours hour by hour. Boise’s bad stretches have run long. 2020 and 2021 both produced extended runs of unhealthy air, and because the valley holds smoke after the flow shifts, "the wind changed" is not the same as "tomorrow is clear." Forecasts are sharpest one to two days out and the page shows the spread.
Shafer Butte above Bogus Basin is the north check at about sixteen miles, and the Owyhees on the far southwest horizon are the other end of the same reading. When Shafer flattens and the Owyhees go but the Boise Front still shows its ridgelines, smoke has arrived. Table Rock three miles east is the middle. When the top of the Zions Bank building goes and downtown disappears from the Boise River, that is the bottom.
Where Boise's smoke usually shows up first, and the places that share its air.
Great Basin and northern Sierra smoke arriving on southwesterly flow crosses the Truckee Meadows before it reaches the Treasure Valley.
In a bad California year the northern California smoke that ends up over Boise pools in the Central Valley first.
Out here two separate things decide your air: what arrives, and whether the ground you live on lets it leave.
Smokeshow is for informational and educational purposes only. It is not health, medical, or safety advice. Forecasts are model estimates and can be wrong, sometimes by a lot. Descriptions of what you might smell, see, or feel are generalizations, not predictions about your body. For decisions about your health, outdoor activity, or air quality safety, rely on official sources like AirNow.gov, the National Weather Service, and your local health authorities, and talk to a medical professional about your own situation.