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ISU Publication #: none - electronic only
Authors: Greg Brenneman
ISU Extension Ag Engineering Spec.
Date: November 1997

With winter just around the corner, snow fences are going up in anticipation of the snows that will surely come. Snow fences are just one of the ways to control drifting snow. To make sure they do the job right without creating more problems, they must be properly placed.

Most snow blows through a good snow fence. Downwind of the fence, the wind slows and drops the snow. The better the snow fence, the more snow it takes from the blizzard. Research shows that the best snow fences are about half solid and half openings. We say that's 50 percent porous, it lets the blizzard through, but still slows the wind.

Wyoming research shows that fences with 50 percent openings form drift lengths up to 25 to 30 times the fence height. If the distance between the fence and road to be protected is less than 30 times the fence height, then the snow drift may reach the road. That can make a drift problem worse, instead of eliminating it. Fences with less open area will have shorter drifts (10-15 times the fence height) but will also store less snow. For best results, keep a 4 ft. snow fence back at least 75 ft. and preferably 120 ft. from the road or driveway you want to protect.

Some longer term solutions to drifting snow include building up roads and driveways so that snow is blown across rather than drifting on to them. Also, living snow fences of evergreens and shrubs can be planted to provide a windbreak. Make sure that they are planted back from the areas they are to protect. A good rule of thumb for Iowa is to allow 100-150 ft. for trapping of snow between the living snow fence and area to be protected.

Keep grass and weeds alongside roadways mowed down in the fall. This vegetation can act as a mini snow fence dumping snow right on the roadway. Leaving cornstalk stubble undisturbed will trap a great deal of snow out in the field and minimize the amount of snow that can drift onto a roadway.

Anywhere there is an obstruction, snow will drift. By strategically placing or removing these barriers, we can minimize problems from drifting snows.

Revised: 1/10/98