I flew from Montana through Oregon, Northern Calif, and SoCal today. Holy Cow! was it smoky today. The whole way was clear and VFR. However, the entire state of Oregon to Shasta was full of smoke. I was surprised how low the visibility appeared even when I could make out some mountains barely at 25 miles. At some points, maybe visibility was 5 to 10 miles. At that point, I climbed to 13.5K to get above it. I did not like it much! I kept imagining how clouds could easily be embedded within the haze where they could not be seen until too late, although not quite as risky as not seeing a mountain. Here is a shot with Mt Shasta.