ask Ian Tyson..
but here is an answer to that same question on another web page/

..."A cold wind from the north.....
I found these cowboy lyrics elsewhere:

You'll ride a black tornado, 'cross the western sky.
Rope an ole blue northern, and milk it til it's dry.
Bull dawg the Mississippi, and pin her ears down flat...
Long before you take this cowboys hat...


and another mention....
A cold wind that blows down towards the U.S border
along the eastern slope of the Rocky Mountains.