Via Laughing Squid:
Last Thursday, December 11, 2014, the Grand Canyon was filled with a sea of fog in a stunningly beautiful and rare weather event. The fog was trapped in the canyon by warm air above in what is known as a total cloud inversion.
The Grand Canyon, or as it's colloquially referred to, your uncles crack after Thanksgiving Dinner. That massive natural crater is just gorges and waiting to be explored.