In the picture above, the smoke layer and the clearer sky are separated out in the lower part of the picture. The sun was looking red in color even at 4 pm. Birds in the backyard appeared a little confused. May be they thought the night is coming earlier. Some started foraging for food before night and others returned to their regular trees for sleeping.
The dust particles and soot in the smoke are efficient at absorbing at all but the longer red wavelengths. An interesting pre-mature "sunset" on Friday the 13th.
A picture of the fire reported by San Francisco Chronicle at
http://www.sfgate.com/cgi-bin/object/article?o=3&f=/c/a/2008/06/13/MN9F1187JC.DTL
