Typically this happens in the interior of large continents, in a protected river valley or on mountain slopes shrouded in mist.

BBC: The quest to see China��s extraordinary frozen fog

Drive just 10km east from Papallacta and you enter the Amazon Basin's cloud forest, which covers the slopes and the valley in green growth.

BBC: Hot springs and hummingbirds in Ecuador

In Waterville Valley, New Hampshire, the ski slopes were almost empty.

CNN: Weather worries prompt school closings in South

The accident took place in at 2, 000m (6, 500ft) above sea level on the slopes of Mount Cermis, in the Fiemme Valley.

BBC: Italy: Russian tourists die in snowmobile accident