New U.S. military base closings "will be tsunamis in the communities they hit," the chairman of the commission that will help decide which facilities survive said Tuesday as his panel met for the first time.

Anthony Principi (search) said the nine-member commission will try to provide a "clear-eyed reality check" of the Pentagon's list of domestic defense installations that should be shuttered or downsized. The Defense Department is expected to release that list next week.

Underscoring the economic impact base closures can cause, the General Accountability Office (search) issued a report stating that communities that lost bases in previous years "are continuing to recover" and have regained about 85 percent of the civilian jobs that were lost. The GAO is an investigative arm of Congress.

While the report said most affected communities are faring well when compared with the average U.S. unemployment and income-growth rates, it added, "The recovery process has not necessarily been easy."

Principi told commissioners, congressional staffers, lobbyists and reporters jammed into a Capitol Hill hearing room, "The ripples of the proposals the secretary of defense will soon present to our nation, and to us, will be tsunamis in the communities they hit."

The warnings from Principi and the GAO demonstrated the enormous consequences of the first round of closures in a decade -- and the daunting task before the Base Closure and Realignment Commission (search).

The Pentagon is putting the finishing touches on its list of which of the country's 425 major military installations to close or downsize. It is seeking to save billions of dollars a year by eliminating extra infrastructure it says was needed during the Cold War but has become obsolete as terrorism became the prominent threat.

Closures in 1988, 1991, 1993 and 1995 eliminated or realigned 451 installations, including 97 major ones, and saved about $29 billion through 2003, according to a report issued Tuesday by the GAO. The report said the Pentagon should save $7 billion annually as a result of the upcoming closures.

Communities across the country are waiting anxiously to see if nearby military facilities will be spared.

States and cities -- and their congressional delegations -- are trying to avoid closures by making the case that their bases are crucial for national security. They have hired high-powered lobbyists with Washington connections and tried to make their facilities -- through new construction and other improvements -- more resistant to closure.

Originally, defense analysts expected more bases would be closed rather than downsized during this round. But defense officials recently have suggested fewer bases than expected will be eliminated to accommodate the estimated 70,000 troops and 100,000 dependents based in Europe who are slated to return to the United States.

Principi swore in the eight other commission members Tuesday. The panelists, made up largely of retired military officers chosen by the president and congressional leaders, spent much of the first meeting listening to analysts give them a history lesson of the base-closing process and a status report of current national security threats.

The few questions that were posed early on focused on whether the Pentagon has the authority to close National Guard (search) bases without the consent of governors. With no clear answer, commissioners suggested a legal opinion may be necessary.

The panel -- with the help of a staff of roughly 60 people -- will spend the next four months reviewing the Pentagon's list to determine whether each base slated for changes meets criteria outlined in the law that authorized the closures.

Four of the criteria relate to the value the facility provides to the military, and, ultimately, to national security. Potential costs and savings, the economic impact on states and cities, the infrastructure of communities and the environmental ramifications also are considered.

The commission will eventually vote on whether to accept or deny the Pentagon's recommendations. It can remove a facility from the list only if it finds that the Pentagon deviated from the criteria. To add a facility to the list, the commission must give Defense Secretary Donald H. Rumsfeld 15 days to explain why the Pentagon hadn't slated it for closure or downsizing.

The commission must send its report to President Bush by Sept. 8. The president will review the report and order revisions if needed. Congress then has to accept or reject the report in its entirety. The closures and downsizings would occur over five years starting in 2006.