By Alejandro Freixes, CCNN Head Writer
The Grand Canyon is a deep canyon that was carved out by the Colorado River, starting roughly 17 million years ago in Arizona. The 277-mile length and up to 18-mile width of the famous national landmark contains about 2 billion years of the Earth’s geological (rock-based) history. While its 6,000-foot depths draw millions of visitors every year for the breathtaking views, a rare fog recently settled across its vast expanses.
Known as a temperature inversion, the unique weather event only takes place every few years, according to the National Park Service that manages the canyon. According to the National Weather Service (NWS), the inversion (flipping) takes place when a layer of cool air gets stuck underneath warmer air.
“Once the sun goes down, the ground loses heat very quickly, and this cools the air that is in contact with the ground,” explained the NWS. “However, since air is a very poor conductor of heat, the air just above the surface remains warm. Conditions that favor the development of a strong surface inversion are calm winds, clear skies, and long nights.”
The NWS added, “Calm winds prevent warmer air above the surface from mixing down to the ground, and clear skies increase the rate of cooling at the Earth’s surface. Long nights allow for the cooling of the ground to continue over a longer period of time, resulting in a greater temperature decrease at the surface.”
As the uncommon foggy event came to an end, the Grand Canyon National Park Facebook page said, “The canyon gave us a second rare inversion in three days. Freezing fog dominated yesterday and is reflected in great patterns on this Kaibab Limestone. By the end of the day the sun was able to burn it all away no doubt making many first time visitors very happy. What will tomorrow bring?”
Images courtesy of Grand Canyon National Park Facebook.