For more than a year, rangers from Whiskeytown planned a full-scale security exercise at Shasta Dam with Bureau of Reclamation staff and other partners from 22 agencies and organizations. That exercise occurred on November 17th and was centered around a simulated multi-faceted terrorist attack on the dam, staff, and visitors. A unified incident command was established, with people and resources assigned to a wide variety of functions. Simulated explosions, a hostage situation, and a simulated large water release were all successfully resolved. NPS rangers were given appropriate assignments by the incident commander, getting to work directly with every law enforcement agency in the Northern California area. Much of the exercise was designed around the successful full-scale exercise conducted at Hover Dam a couple of years ago in which Lake Mead rangers played a major role. Shasta Dam holds back the largest reservoir in California and is the second largest dam in the U.S. It was identified as a critical U.S. infrastructure after 9/11.