South Dakota winter like no other
In South Dakota you can expect two things about winter: snow
and blowing snow, but what happens when you take a state that in some extent
relies upon winter recreation for income and there is none of the white
stuff. For the 2011-2012 winter season,
South Dakota has seen less than 10 inches of snow well into March. Only two snow storms have occurred, one prior
to Thanksgiving and another just the other day.
At times there have been snow flurries that never required plowing, but
now with a full snow storm behind us the ground is white and the second thing
about winter in South Dakota is happening.
In many ways blowing snow is worse than snow. When you plow snow its moved and no longer an
issue, but blowing snow is relentless in its quest to cover everything with a
layer of snow. Drifting and moving like
a sand dune blowing snow works its way into everything. Blowing snow can exist in two main methods. Either
as pillow drifts largely disconnected from other pillow drifts or figure drifts
which work their way outward from an object or sign onto a surface. Both occur at the same time and how large the
drift gets depends on wind speed, wind direction, nearby obstructions, and friction.
Wind speed and direction play the ultimate role in blowing
snow. If wind speed is slow, drifting formations will occur more rapidly where
as if winds are fast drifting snow isn’t as readily apparent. If the direction
of the wind changes, wind itself can move the drift to a new location or
removing it completely. Think of blowing
snow as a leveling force, where any change in elevation will be filled in with
snow this can be especially tricky with pillow drifts where as the number of
drifts increase in size, the total surface will become covered as the leveling
force takes over.
Such is the case in South Dakota, if the snow event wasn’t
bad enough the blowing snow that follows will ensure you many hours of plowing
the same piece of pavement repeatedly until either the wind changes direction,
speed, or the snow turns to ice. But ice is a different story…