Chinook Arch Cloud Sunrise

Chinook Arch Cloud Sunrise, originally uploaded by gnpToday.

One of the most striking features of the chinook is the chinook arch, which is a band of stationary stratus clouds caused by air rippling over the mountains due to orographic lifting. To those unfamiliar with the chinook, the chinook arch may look like a threatening storm cloud at times. However, they rarely produce rain or snow. They can also create stunning sunrises and sunsets.
The stunning colors seen in the chinook arch are quite common. Typically the colors will change throughout the day, starting with yellow, orange, red and pink shades in the morning as the sun comes up, grey shades in the mid day changing to pink/red colors, and then orange/yellow hues just before the sun sets.