10:15 a.m. September 11, 2001: NORAD Operations Center Closes Blast Doors Due to Warning of Hijacked Plane

Blast doors at NORAD headquarters in Cheyenne Mountain, Colorado. [Source: Eugene Chavez]The FBI has issued a warning that a plane originating in San Diego might be hijacked and specifically targeting Cheyenne Mountain, Colorado, where NORAD’s operations center is located. In response, the massive steel doors designed to protect the mountain from a nuclear blast are closed for the first time in its history. One report suggests, however, that these doors are closed in response to the US military being put on high alert (see (10:10 a.m.) September 11, 2001). The NORAD operations center is also informed that a Ryder rental truck driven by “Arab-looking men” and packed with explosives is heading their way. Lt. Col. William Glover, chief of NORAD’s air defense operations, says, “It didn’t make sense, but those phone calls were happening.” [Toronto Star, 12/9/2001; Aviation Week and Space Technology, 6/3/2002; BBC, 9/1/2002]