towns effect from fire?

Question

My town turns brown and gets a gross cloudy haze every afternoon because of a fire miles and miles away. and then everything gets covered in a very fine coat of ash. But it only starts in the afternoon, and the fire's been burning for weeks. what is it about the night and morning that keeps the ash and smoke out of my town?

I live in bakersfield ca(the valley aka smog net) and the fire is in santa barbara ca

Answer 1

There's probably a strong early morning temperature inversion that traps the smoke and ash near the ground at the fire site, as the day goes on, the ground heats up and hot "bubbles" of air (called thermals) rise up through the inversion and carry the pollutants higher. Also, later in the day the land heats up more than the ocean and the sea breeze starts, which carries the smoke inland from Santa Barbara to Bakersfield.

Answer 2

It's likely the result of differing wind flow. You're in Bakersfield, which is in the southern San Joaquin Valley. At night into the early mornings the atmosphere typically has what is known as an inversion, where a layer of relatively warmer air exists over the cooler air at the surface. Smoke and fine ash from the fire does not rise above this layer and thus moves in a different direction (maybe even blocked by the mountains to your west. In the afternoons the inversion is lost as the surface air heats, and the smoke rises higher. As the smoke gets higher it encounters a different wind direction and moves with it. I see that the current mid-level wind flow is basically from Santa Barbara northeast across Bakersfield. Once this mid-level wind flow changes, you should see an end to the smoke and ash.