The Chinook Arch November 14, 2001 The above photo was taken at
evening twilight in Calgary, Alberta by Jeff McIntosh. On the
lee (eastern) side of the Rocky Mountains in Colorado, Wyoming,
Montana, and the province of Alberta in Canada, chinook winds
occasionally bring respite from cold weather. Chinook is an
Indian name meaning "snow eater." These warm, westerly winds
result from downslope winds - air moving across the Rocky
Mountains and down onto the prairies. During those cold, dull
gray winter days, Albertans sometimes look toward the mountains
for the Chinook Arch, a curved patch of blue sky (as shown
above) that indicates that warm winds are approaching. Over this
past weekend, a strong chinook was felt in Alberta and Montana.
Chinooks typically occur from early November to late March.