Niwot Ridge

Niwot Ridge, an area of alpine tundra, is located about 22 miles (35 kilometers) west of Boulder, Colorado, and more than 9,843 feet (3,000 meters) above sea level. The ridge and the adjoining Green Lakes Valley cover approximately 3.8 square miles (10 square kilometers.) Runoff from the mountains feeds the Colorado and Mississippi Rivers.

Alpine tundra in the Rocky Mountains generally begins forming from 4,000 to 10,000 feet (1,219 to 3,048 meters) above sea level. Since its elevation is fairly high, Niwot Ridge is characterized by low temperatures throughout the year. The annual mean temperature is 5°F (-3.7°C). Temperatures in January average about 8°F (-13.2°C) and in July about 47°F (8.2°C).

This tundra is surrounded by subalpine forest at the lower elevations. Where the forest and tundra meet, subalpine meadows and patches of krummholz (dwarf trees) exist. Other physical features include a cirque glacier, a type of U-shaped glacier with...