I experienced a chinook in Calgary in '98. Fascinating. We walked to work in a freezing blizzard in the morning, it was below freezing. Then we had lunch in the office in a room without windows.
In the evening we put all our heavy clothing on, hats, mittens and scarves and went out into ... Blue sky, Warm winds, 70 F and HUGE puddles of water everywhere. We were completely perplexed.