I am utterly heartbroken, but there is a massive search and rescue effort being coordinated on FaceBook:
http://www.facebook.com/groups/440281472678391/
Please feel free to join the group to help (if you are in the East Bay Area of California) or just to follow along with the search effort. Please send good thoughts, prayers, cross your fingers, whatever you do when wishing for a beloved dog to return home.