The Carpenter 1 fire has now grown to 20,000 acres and is being fought by nearly 800 firefighters.
Smoke tends to billow up into the sky in the late afternoon because it is suppressed by cooler air sinking in the morning. That is why the smoke plume appears to grow in the afternoon.
Cooler air holds the smoke lower to the ground in the morning, spreading it throughout the valley. As air warms and rises during the day, the plume becomes more defined and flows higher into the atmosphere.
Here is a link to the National Oceanic and Atmospheric Administration’s website showing the plume.