Chapter 12.pdf - 1 About 200 million years ago tectonic...

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1. About 200 million years ago tectonic forces began moving the North American Plate westward. It eventually collided with the Pacific Plate and the force of the collision, called Columbia Orogeny moved east over North America, cracking enormous masses of rock and the sedimentary layers up and over the adjacent side. This process created the main ranges of the western and central Rocky Mountains. 2. This is because of height. The Appalachian Mountains average about 3000 feet in the height with the highest peak ~6800 feet, where the Rocky Mountains can reach up to ~14,500 feet with vegetation zones at ~4000,~6000,~8000,~10,000, and ~12,000. 3. Chinook winds are associated with very dry, wair air that descends from the mountains to the eastern foothills and plains,especially in the winter. Towns and cities located on the front ranges commonly experience 20 to 30 F increases in temperature with significant drops in humidity in short time periods.
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  • Spring '14
  • EricC.Ewert
  • Rocky Mountains

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