Winter Snow Management | Snow Fences

    Blowing and drifting snow creates cleanup issues during a winter storm. When roads, walkways and stairs are constantly blown in after the snow stops falling the cleanup required can extend well after the storm has finished depositing snow.

    A simple, time tested method of trapping blowing snow can help. A snow fence can be set up to trap and store blowing snow and when installed correctly, can save time, energy and prevent potential slips and falls.

    Snow fences work by lowering wind speed and therefore reducing its snow carrying capacity. Most of the snow is deposited on the downwind side of the fence.  

    Two key design properties are crucial – 1) The height of the fence and 2) its placement relative to the area to be protected.

    In general terms a higher fence will store more snow. In practical terms, on areas such as a college campus, a 4-6’ tall fence works well. Multiple fences placed in rows can be used to increase snow storage without additional height. Porosity of the fence materials will effect performance. Horizontally slatted fences work best but are not always the best choice for a campus. Plastic snow fencing material is available in different lengths and works well. Make sure to purchase material designed for use as a snow fence. Safety fence may not have the 40-50% porosity which will provide the best results. Stake the fence at 6-8’ foot increments and remember to keep the fence upright because after the ground freezes resetting stakes is difficult.

    The fence should be placed what seems like a long way from the area to be protected but the results hold up. Fences should be placed 35 times the height from the area to be protected. For example: a 4 foot fence should be placed 140 feet away. Remember you are creating a snow storage area on the downwind side of the fence. Placing the fence too close will store snow onto the area you are trying to protect.

    The fence should be set up perpendicular to the prevailing wind and extend well beyond the area to be protected. Fences should extend 20x the height beyond the area to be protected to account for trapping inefficiencies at the end of a fence and variability in wind direction. There is some leeway in the exact placement perpendicular to the wind, departures of up to 25 degrees will still provide protection.

    Leave a 10 - 15% gap between the bottom of the fence and ground level. The scouring effect created by this gap will form the resulting snow bank. For example: a 4’ fence requires a 5 - 8” gap. Placing the fence directly on the ground greatly reduces its effectiveness.

    Snow fences intended to protect roadways are most effective if 8’ or higher.

    Key Points

    Stake the fence securely.

    Fence should be placed 35x the height from area to be protected.

    Fence porosity of 40-50% works best.

    Leave a 10% gap between the bottom of the fence and the ground.

    Extend the fence 20x the height past the areas to be protected.

    Place the fence perpendicular to the prevailing wind. Up to a 25 degree departure from perpendicular is acceptable.

    *Any Comments Will Be Directed Back to the Author - Ted Heywood, CGM*

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