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The Anatomy of a Snow Ghost
Brian Schott: February 22, 2011
These are some recent photos of skiing among ghosts --
snowghosts, that is. Whitefish is famous for them. The casual observer mistakenly thinks that these trees are encrusted with snow, while others erroneously called the coating hoar frost. The truth is that the cover is heavy accretions of ice -- called rime.

The architects of snow ghosts are the winds, clouds, and fog that frequently buffet and blanket the ridge tops and summit of the mountain. Even though these clouds are colder than the freezing temperature of water at 32 degrees Fahrenheit, they are made of masses of suspended, liquid, water droplets.

These super-cooled water droplets can exist in a liquid state between 32 and minus 40 degrees because they lack freezing nuclei. These droplets freeze, however, when they encounter ridge top and summit obstacles - like trees and lift towers and buildings, and even skiers and snowboarders if we sit still.

The resulting coating is rime ice. This process is akin to taking very small, but multiple buckets of cold water and splashing them upon these objects and causing them to freeze into a thick accretion of ice.

Punch into one of these coated trees the next time you have the opportunity. You will quickly realize that this is not just a soft coating of snow, but instead a hard, heavy accumulation of ice. A quick calculation reveals that the weight of these masses can easily be in the multiples of tons on larger trees. Throw in gusty winds that create swaying action back and forth and it is easy to see how extensive damage is possible. Stand back and be alert if there is a chance of breakage.

Rime is not all bad however. Light accumulations act as a barrier, protecting the tree and its needles from the abrasive action of blowing ice, and the drying of cold winds.

But beyond the technical mumbo-jumbo, what we have are haunting, beautiful snow formations that are a signature of Whitefish. Skiing or snowboarding through them is an experience like no other.

Photos

Snow ghosts in Hellroaring Basin, February 2011.
Slashing through snow ghosts, Hellroaring Basin, February 2011.
Snowghosts in Hellroaring Basin, February 2011.
Snowghosts at Whitefish.