Winter transforms Yellowstone  into an extraordinarily beautiful place where the fires and brimstone of hell meet the bitter cold and snow of winter.
The snow often averages four feet in depth but can exceed 10 feet on mountain passes. The snow is usually quite dry, although late in the season conditions deteriorate as temperatures rise. Early in the winter or after major storms, backcountry skiing can be difficult because of the deep powder.
Temperatures are generally in the 10-25°F range during the day, while nights frequently dip below zero. (The record is -66°F, recorded on February 9, 1933.) Winds can make these temperatures feel even lower, so visitors should come prepared for extreme conditions.
The thermal basins are a real wintertime treat. Hot springs that are simply colorful pools in summer send up billows of steam in the winter, coating nearby trees with thick layers of ice and turning them into “ghost trees.”
The geysers put on astounding displays as boiling water meets frigid air; steam from Old Faithful  can tower 1,000 feet into the air! Bison and elk gather around the hot springs, soaking up the heat and searching for dried grasses, and bald eagles are often seen flying over the heated waters of Firehole River. The bison are perhaps the most interesting to watch as they swing their enormous heads from side to side to shovel snow off the grass.
Grand Canyon of the Yellowstone  is another place transformed by the snow and cold. Although the water still flows, the falls are surrounded by tall cones of ice, and the canyon walls lie under deep snow.