Even though the weather has been unseasonably mild, snow is inevitable. Rural landowners can be better prepared to deal with drifting snow if they erect snow fences, according to Greg Brenneman, agricultural and biosystems engineering specialist with Iowa State University Extension and Outreach.

These barriers, either constructed from wood or plastic, prevent snow from blowing across farm fields and blocking streets or driveways.

Some snow fences are better than others. “Research shows that the best snow fences are half solid and half open,” he said. “Fifty percent porous snow fences let blizzards blow through the slats, but still slow the wind.” These fences force drifts to form downwind.

In the past, wooden picket fences were often used for snow fences. But Brenneman said plastic snow fences are preferred today because they cost less and are lighter weight. However, fencing materials differ in quality, and plastic fences designed as safety fences are not as heavy duty as those specifically designed as snow fences.

Snow fences must be properly placed in order to prevent more problems, he said. 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,” he said. For best results, he advises landowners to keep 4-foot snow fences at least 80 feet, and preferably 120 feet, from a road or driveway.

Brenneman provides the following tips for proper snow fence installation: Locate the fence perpendicular to the prevailing wind direction, make it as long as possible, leave a bottom gap of 6 inches, and ensure that steel posts are on 8-foot centers. He also recommends that end posts be braced with a steel post driven into the ground at an angle and securely wired to the fence. Plastic fencing materials should be sandwiched between two wood laths and wired tightly to the steel post at the center and near the top and bottom.