In 1940, the United States faced its most direct threat of invasion since the War of 1812. Tensions between America and Japan were at a boiling point, as war in Europe had erupted into full-blown open warfare.Due to these threats and the fall of France, the U.S. government decided to expand ammunition storage facilities across the country. The initial plan was to place a facility in each of the four corners of the United States to repel an invasion should it occur. Sierra Army Depot was one of those facilities.Construction began on the depot in early 1942 near Honey Lake on the California and Nevada border. By the end of the war, there were 1,021 buildings on the installation with a primary focus of storing ammunition. Of those buildings, 802 were ammo storage igloos.Fast-forward 50 years to another time, requirements for the Army have changed and all sections of the Department of Defense had to examine what missions needed to continue. During the Base Realignment and Closure Commissions 1995 round of talks, DoD leadership decided that the ammunition storage mission at Sierra Army Depot was no longer needed and the depot was set to close.According to Kathy Ayers, the production operations manager for the depot, the commander of the installation during the draw down was successful in convincing the Department of Defense to keep the depot open by drawing attention to the general supply and storage capabilities that Sierra had to offer.The ammunition storage mission at Sierra fully drew down before the end of the 1990's then picked up its new mission of receiving, storing, upgrading, configuring, assembling, shipping, and accounting for a wide range of Army supplies, vehicles, and equipment.Ayers has been at the Depot since the 90's and she says the mission has grown to a point where every building on the installation is either used for production or storage, including the 801 surviving igloos.The igloos, which are 26.5 feet wide and up to 50 to 60 feet long, have blast doors that were narrow, thick, and reinforced around the sides by thick concrete walls. The doors were so narrow that forklifts were unable to move in and out and workers had to move everything stored there by hand.Due to the increase in the depot's mission, Ayers says that the current commander decided to renovate the igloos to make it easier and faster to access the equipment and materials inside.Steve Balmer is the manager of the Reutilization Operation Group at Sierra. He says depot leadership decided to remove the blast doors on the igloos, cut away some of the concrete wall, and widen the door opening. They also decided to replace the blast doors with lighter weight roller doors that would allow forklifts to move in and out of the structure more easily.Although only 50 of the igloos have undergone the retrofit, Balmer says, "they can store major assets and the deterioration [inside them] is not as bad as it would be in other places…because of the low humidity…it arrests the deterioration of materials that are stored here."Through ingenuity on retrofitting the base facilities to accommodate and expand the depot's current mission, Balmer says that Sierra is now in a better position to assist with bringing equipment back from Iraq and Afghanistan. He says, "with the retrograde and reutilization mission bringing things back from Southwest Asia inspecting them to determine what is serviceable and what is not…cleaning them and putting them back in the inventory saves the taxpayers money."Kevin Pasley, Sierra Army Depot budget officer, says the decision to retrofit the igloos was the only plausible decision to consider at the time because there were too many administrative and financial obstacles to building newer facilities and the renovations saved a lot of money.The renovated igloos will allow Sierra Army Depot to contribute to two of the seven key Army Materiel Command focus areas of Industrial Base Readiness and Supply Availability and Equipment Readiness. AMC has the overall goal to ensure the joint force is prepared for large-scale combat across land, sea, air, space and cyberspace in support of join, Multi-Domain Operations.