Evacuations
According to a letter to the editor of the The Washington Post after the September 11 attacks, most of the congressional leadership was evacuated to Mount Weather by helicopter.
Between 1979 and 1981, the National Gallery of Art developed a program to transport valuable paintings in its collection to Mount Weather via helicopter. The success of the relocation would depend upon how far in advance warning of an attack was received.
Read more about this topic: Mount Weather Emergency Operations Center