The forests of the arid Western US have a fire-based ecology. Fires are a normal part of the forest regeneration process, and without all of us pesky humans, naturally occurring wildfires would be no big deal as far as Mother Nature is concerned. But we WILL build our homes and cities in and around the forests, and thus fires like the Pole Creek fire, 6 miles west of Sisters OR is a very big deal.
Here is one of the waves, coming in low and backlit by the sun.
Here you can see another cloud higher up, through the lower level smoke.
Of course Bend isn't getting the worst of it, as we are 20 miles or so away from the fire. Towns and folks on ranches closer to the fire are really having a tough time. Here is a cool photo from NASA, showing the Pole Creek fire and other big fires currently burning around the West:
Our normally fabulous warm, clear, sunny fall days are now a bit of a curse, as there is just about zero chance of rain for weeks and weeks. So we check the wind direction before setting out into the woods for a bike ride, hike or just a walk around the neighborhood, and try to spend as little time outdoors, breathing smoke, as we can. Readers, please think rain (but not lightning).