On Sunday the 21st, I took this picture of a cumulus cloud over the Boise mountains. What makes it unique is its source. The Pioneer Fire is creating rising warm air. As the air rises, it cools. When air is cooled below the dew point, water condenses out. This releases more heat and causes the air to become even more buoyant. And as a result, the air rises faster and condenses even more water out to create a cumulus cloud.
You can see the smoke from the fire below the cumulus cloud. The name of this cloud is pyrocumulus.