[1] During the last year of World War II, Slemon was Deputy Air Officer Commander-in-Chief of the RCAF Overseas.

[2] On 5 October 1960, warning lights in Cheyenne Mountain Complex indicated that the BMEWS site in Thule, Greenland was detecting a possible ICBM attack.

[3] His next call was to NORAD's second-in-command, Slemon, then located in Cheyenne's counterpart at CFB North Bay.

While the call was being connected, the alert status went to level 4, and then 5, indicating the BMEWS site was almost positive an attack was underway, and giving Slemon the authority to order the immediate release of SAC's Airborne Alert force for attack on the USSR.

In particular, the signal timing seemed to indicate the targets were at a very long distance, while the computer was reporting they were about 2,200 miles (3,500 km) away.