Grand Canyon fills with fog
Dense clouds at the south rim of the Grand Canyon in Arizona, Dec. 11, 2014. A rare weather phenomenon called a "total cloud inversion" occurs when clouds are forced down by warm air and can't rise.
The total cloud inversion usually happens every few years and is expected to hang over the Grand Canyon just below the rim throughout the day.
Read More: Grand Canyon fills with clouds
Grand Canyon National Park
Dense clouds at the south rim of the Grand Canyon in Arizona, Dec. 11, 2014.
The total cloud inversion is expected to hang over the Grand Canyon just below the rim throughout the day.
Grand Canyon National Park
Visitors to Mather Point on the South Rim of Grand Canyon National Park, Ariz., view a rare weather phenomenon - a sea of thick clouds filling the canyon just below the rim, Dec. 11, 2014.
Cory Mottice of the National Weather Service said the weather event usually happens once every several years, though the landmark was treated to one last year.
Grand Canyon National Park
In the past few days, the sweeping vistas of the Grand Canyon have been replaced by an equally stunning view, Nov. 29, 2103.
Due to a rare weather phenomenon, the canyon was filled with fog, giving onlookers the illusion that they were high above the clouds.
The National Weather Service has posted a breathtaking series of images of this weather event, called a temperature inversion.
Grand Canyon National Park
Temperature inversions usually happen in winter, when longer nights cause cool air to become trapped beneath warmer air, Nov. 29, 2103.
Grand Canyon National Park
The fog-filled canyon as seen from Mather Point, Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29. 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
Clouds all the way to the horizon in the Grand Canyon, Nov. 29, 2013.
Grand Canyon National Park
A view of the canyon's South Rim, covered in fog, Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
A vertical panorama of frosted plants, with the foggy canyon in the background, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
A view of the fog-filled canyon from Mather Point. NPS photographer Erin Whittaker wrote, "Rangers wait for years to see it. Word spread like wildfire and most ran to the rim to photograph it. What a fantastic treat for all! ", Nov. 29. 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, taken just after 8 a.m, Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
NPS photographer Erin Whittaker wrote, "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.", Nov. 29, 2013.
Grand Canyon National Park
A view of the Grand Canyon filled with fog due to a temperature inversion, Nov. 29, 2013.
Grand Canyon National Park
The North Rim's Grand Canyon Lodge above the clouds, Nov. 29, 2013.