A snow roller.
(Courtesy: Miranda Granche at flickr.com)
A freshly fallen snow clinging to the lawn and tree limps and forming drifts in the corner of walls can be a beautiful sight that causes many people to love the snowy months of winter. Sometimes, however, some very weird things can take place in the cold, wind and snow of winter.
For example, have you ever heard of snow rollers? Snow rollers appear to be large barrels of oil drums or small roll of toilet paper-like masses of snow. They usually appear in the winter where the terrain is hilly or even mountainous and form when strong winds blow moist snow along the ground that masses into a cylinder-shaped ball with a hollow center. When it gets too heavy to move by the wind, it stops where it lies.
Then there is hoarfrost, ice that surrounds a plant or tree limp that slightly resembles the gray bristling hair of an old man’s beard. This occurs when water vapor or mist is in the air over cold ground that is about at freezing temperature of 32° F during the winter months. When flowers or bushes cool to a temperature well below freezing on a clear night when their heat radiates upward, then hoarfrost forms. The more the moisture in the air, the more complex the ice crystal patterns on the flower or branch.
Hoar frost.
(Courtesy: P.J. Johnson at flickr.com)
Finally, there is thunder snow or a heavy snowstorm accompanied by lightning and thunder in the winter. This occurs during very heavy snowfall with snow falling the rate of an inch or so an hour or more. Above the layer of snow clouds are pockets of unstable air. When air temperatures fall to between 14° F and -4° F snow and hailstones form in the pockets of air and as the snowflakes and hail collide, static electricity occurs and builds up causing lightning and thunder in a snowstorm.
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