Mural in Motion
Some days, especially in summer, the clouds of central Colorado present a spectacular skyscape constantly changing and shifting from puffy cotton balls to ominous thunderclouds to occasional bright blue skies of the American West. One such day was last Sunday and the following time-lapse video captured the scene:
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Why the clouds?
The Rocky Mountains, as with all imposing mountain chains, affect weather and climate in a number of significant ways. Summertime heating of the mountain slopes causes one of the more majestic effects, the regular, almost daily, development of thundershowers over the higher terrain.
The Rockies in central Colorado reach elevations just above 14,000 ft (4267 m), about one-third of the way up into the troposphere (the layer in the earth’s atmosphere closest to the ground where most of our weather and clouds form). When the sun warms a high-elevation mountainside during the day in summer, that heat is quickly transferred to the atmosphere. Putting a heat source at 14,000 ft up in the troposphere, a level where the atmosphere is usually chilly, causes convection, the rising of air due to heating. Even on relatively dry days with only a meager amount of moisture in the troposphere, the convection caused by the elevated heat source of the mountains is so strong clouds can still form. If there is enough moisture, those clouds will become showers and thundershowers.