Hot and dry Santa Ana conditions across southern California (with wind gusts as high as 91 mph in Los Angeles county and 87 mph in Ventura county) caused widespread blowing dust/sand (reducing surface visibility to 3 miles at Ontario, station identifier KONT) and created an environment that allowed several large wildfires to burn out of control on 21 October 2007. Note that the dew point temperature at Ontario dropped from 50ÂºF (+10Âº C) down to +2ÂºF (-17Âº C) in a 3-hour period once the strong northeasterly Santa Ana winds developed. AWIPS images of the GOES-11 3.9 Âµm IR channel (above) showed very hot pixels (black to yellow to red enhancement) associated with the larger fires (including one fire that caused multiple injuries and at least one fatality near San Deigo, and another fire farther to the north near Malibu – just northwest of Los Angeles KLAX – which shut down portions of the Pacific Coast Highway).
The IDEA MODIS Aerosol Optical Depth product (below) and GOES-11 visible imagery (QuickTime animation) revealed several large plumes of smoke (which could have also contained some blowing dust and/or blowing sand) drifting westward over the adjacent offshore waters of the Pacific Ocean. The airborne particulate matter was causing air quality problems at several sites across southern California on that day.