Snow fence
Encyclopedia
Sand fence
A sand fence is a structure similar to a snow fence used to force wind blown, drifting sand to accumulate in a desired place. Sand fences are employed to control erosion and to recruit new material in desert areas....
, that forces drifting snow
Snow
Snow is a form of precipitation within the Earth's atmosphere in the form of crystalline water ice, consisting of a multitude of snowflakes that fall from clouds. Since snow is composed of small ice particles, it is a granular material. It has an open and therefore soft structure, unless packed by...
to accumulate in a desired place. They are primarily employed to minimize the amount of snowdrift
Snowdrift
A snowdrift is a deposit of snow sculpted by wind into a mound during a snowstorm. Snowdrifts resemble sand dunes and are formed in a similar manner, namely, by wind moving light snow and depositing it when the wind is slowed, usually against a stationary object. Snow normally crests and slopes...
on roadways and railways. Farmers and ranchers may use temporary snow fences to create large drifts in basins for a ready supply of water in the spring. In the ski industry snow fences are used to catch snow to increase snow depth in specified areas; a practice which may also be considered snow farming
Snow farming
Snow farming is the use of obstacles, equipment and knowledge about management of snow in order to strategically manipulate snow coverage. Often this is done for the purpose of skiing or even preventing snow drift in certain areas like roads...
. Snow fences are also used in avalanche control
Avalanche control
Avalanche control or avalanche defense activities reduce the hazard avalanches pose to human life, activity, and property. Avalanche control begins with a risk assessment conducted by surveying for potential avalanche terrain by identifying geographic features such as vegetation patterns,...
.
Temporary snow fences in North America are usually one of two varieties: perforated orange plastic sheeting attached to stakes at regular intervals (the type usually used for construction site
Construction Site
Construction Site is a television series created by The Jim Henson Company in 1999, and consists of 7 construction vehicles. The show was broadcast on ABC Kids for a while, and had a range of videos. It was originally produced for and shown on CITV starting in 1999. In 2000 it was nominated for a...
fencing or temporary sports field fencing), or a cedar or other lightweight wood strip and wire fence, also attached to metal stakes. A permanent snow fence generally consists of poles set deeply into the ground with planks running across them, or a line of closely spaced shrub
Shrub
A shrub or bush is distinguished from a tree by its multiple stems and shorter height, usually under 5–6 m tall. A large number of plants may become either shrubs or trees, depending on the growing conditions they experience...
s or conifer trees. A permanent snow fence may be installed where a roadway or railway is subject to predictable snow and wind patterns each winter, such as mountain pass
Mountain pass
A mountain pass is a route through a mountain range or over a ridge. If following the lowest possible route, a pass is locally the highest point on that route...
es
Snow fences work by making the wind speed on the downwind side and near upwind side less than that on the far windward side, causing blown snow to settle to the ground.