As with Offutt (SAC home base), Ellsworth, Whiteman (home of the B2 bomber), FE Warren, Malmstrom, and Minot Air Force bases ("why not Minot? Freezin's the reason"). These are Bomber, Tanker air refueler, and ICBM missile launch bases. They are situated far from the coastline to provide maximum warning and response time before being struck from sub launched missile attacks. Post WWII and Cold war thinking.
On SAC bases there and also closer to the coast, air flight crews lived in the Alert Facility immediately adjacent to their parked aircraft for a week at a time on a rotating basis. "Milssile Moles" lived underground for the duration. I remember a few times when tensions were so extra high that we literally lived on board the aircraft to save the 30 seconds that it takes "when the Klaxon horn goes off" to run through the facility exit tunnels to the aircraft, so that we could get off the ground that much faster. Each week featured at least one practice unannounced deafening klaxon blast to run out to your aircraft. On board, the navigator receives and decodes an encrypted radio message instruction, co-pilot verifies the decode, Pilot starts engines, hold brakes, receive another message and (hopefully) shut down. The message rarely included instruction to taxi to the runway hold line within xx minutes and another to stand down, turn around, reset to our original parking slot. Until the first received message is decoded, we never knew for sure if it was practice or real to take off and fly our planned mission heading north.
Watch the 1955 movie "Strategic Air Command" with Jimmy Stewart for a Hollywood rendition of what it was like.