The NOAA Hazard Mapping System Fire and Smoke Product image above shows that there is a heavy concentration of smoke crossing diagonally across the United States.
The NOAA Aerosol Watch image above supports this claim as there is an increased concentration of AODs crossing across North America.
The Copernicus Global Forecast image above shows an increased concentration of Biomass AOD concentration meaning the smoke shown is most likely due to a large forest fire.
The NRL/Monterey Aerosol image above shows that there is are multiple sources of smoke surface concentration with an especially large concentration in the Northern California region. The maximum smoke surface concentration reaches above 512 ug/m**3.
The AirNow Map image above shows an increased concentration of particulate matter in Northern California. The maximum air quality index reaches Hazarous levels (301-300, Maroon). INCIWEB reports that in that region there are multiple fires such as the Dixie Fire, the McFarland Fire, the Monument Fire, the River Complex Fire and the McCash Fire which together have burned close to 900 thousand acres of land.