The Santa Ana winds continued to blow today in southern California. Dust storms have now combined with several large wildfires, including fires in Malibu that caused highway closures and evacuations. Fine particle concentrations were code orange, red and purple (AIRNow image, left) in the region. The code purple was in Riverside county-- PM2.5 concentrations reaching 337 ug/m3--with significantly elevated concentrations at other monitors in Ventura and the Imperial Valley (CARB plot, right).
MODIS aerosol optical depth data clearly shows dust and smoke plumes over the Pacific ocean due to the east to west Santa Ana winds. On the right is the MODIS true color image from Terra, when the plumes were still pretty small. Smoke is gray, dust is yellowish. As of just after midnight EST, the processed true color image is only partially available, but it shows huge smoke plumes.