Actually this is an anomalous event for the US. It’s extremely rare for smoke densities this high to cover this amount of area. Out west you only experience this is you are directly downstream from a fire and certain topographic features keep it bottled in specific areas. My AQI is 234 which is higher than most of the areas directly adjacent to the actual fires.
Northern California has had three such events in the past six years. The outfall from extreme forest fires has become far more common.