Clouds fill Grand Canyon in rare weather event

December 11, 2014
This photo provided by the National Park Service shows dense clouds at the south rim of the Grand Canyon on Thursday, Dec. 11, 2014 in Arizona. A rare weather phenomenon on Thursday had visitors looking out to a sea of thick clouds. The total cloud inversion is expected to hang over the Grand Canyon just below the rim throughout the day. (AP Photo/National Park Service, Maci MacPherson)

A rare weather phenomenon at the Grand Canyon had visitors looking out on a sea of thick clouds just below the rim.

The total cloud inversion is expected to hang inside the canyon throughout Thursday.

Cory Mottice of the National Weather Service says the happens about once every several years, though the landmark was treated to one last year.

The fog that has been shrouding parts of northern Arizona is courtesy of recent rains. Mottice says the fog is able to stick around and built up in the Grand Canyon overnight when there is no wind.

With an inversion, the clouds are forced down by warm air and unable to rise.

Mottice says the Grand Canyon gradually will clear up in the coming days.

This photo provided by the National Park Service shows dense clouds at the south rim of the Grand Canyon on Thursday, Dec. 11, 2014 in Arizona. A rare weather phenomenon on Thursday had visitors looking out to a sea of thick clouds. The total cloud inversion is expected to hang over the Grand Canyon just below the rim throughout the day. (AP Photo/National Park Service, Maci MacPherson)

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