Last week's wildfires in Southern California fired up the ratings of each of the network nightly newscasts, with ABC's World News With Charles Gibson drawing its largest audience since February. (A Gibson-hosted 20/20 special on the fires Tuesday night also performed well in the ratings.) With Gibson reporting from the fire lines, the newscast averaged 9 million viewers for the week. NBC Nightly News With Brian Williams recorded about 440,000 fewer viewers. Williams flew to California too, as did CBS's Katie Couric whose newscast averaged 6.6 million viewers. Among the key group of adults 18-49, the Gibson newscast again led with 2.8 million followed by NBC with 2.6 million and CBS with 2 million.