Snow Fences Spell End of Blocked Highways
New snow fences keep Minnesota highways free of drifts and open to traffic.
The Challenge
Southwestern Minnesota is a region of open farmland with low rolling hills. When winter settles in, the region sees average snow accumulations of 1,190 mm to 1,320 mm (47 in to 52 in). "Of course, with 40 mile an hour winds [64 km/h], it blows around so much it's hard to tell how much snow there really is," says Duane Pingeon of the Minnesota Department of Transportation (DOT).
Where hills, overpasses, and other geographic features create the right conditions, snow forms deep drifts on Minnesota's highways. Keeping these highways safe and open to traffic takes lots of time, money, and equipment. Knowing that it would be easier to prevent the drifts in the first place, Minnesota DOT decided to try snow fences, a technology evaluated and enhanced under the Strategic Highway Research Program (SHRP).
Putting the Technology to the Test
Minnesota DOT uses several types of snow fences along roads in the southwestern part of the State. The DOT uses both all-wood snow fences and new fences made of a plastic mesh mounted in a wood frame. The plastic mesh snow fences cost approximately $2.65 per meter ($8.68 per foot) to use per season. The DOT also pays farmers to leave several rows of corn standing along roads during the winter to help control drifting snow.
Snow fences have been used on several roads in the State. They were used along Highway 60 near Worthington for 2 years, and they protect parts on Interstate 90 and Highway 14 near Springfield.
On Interstate 90, Minnesota DOT has installed snow fences where ramps and bridges would otherwise cause drifts. "The snow normally gets 2 to 3 feet deep [0.6 to 0.9 m] after the bridge piers," says Pingeon. "The snow fences help plows keep up."
Snow fences have also been extremely effective near Worthington. "For 20 or 30 years they had problems on Highway 60 with drifting snow. For the last 2 years, we've had no accidents at all." Now, several hills have been graded to prevent drifts, making snow fences unnecessary.
Wherever snow fences are in place, visibility is much better and the road stays much clearer, thus improving safety for motorists. Pingeon says this is the biggest benefit. "If we save one life, the snow fences are worth the cost."
The fences help the Minnesota DOT do its job more cost effectively. Now that roads are no longer buried by huge drifts, the DOT can keep roads open with more efficient side plows, which only work well when the snow is no more than about 0.3 m (1 ft) deep. Without snow fences, the DOT would have to send out V-shaped plows mounted on the DOT's larger trucks to break open snow banks.
Because roads now stay relatively free of snow, the Minnesota DOT saves money. "If we get a 5 to 8 inch storm [127 mm to 203 mm], we don't have to send out as many snow blowers or plows," Pingeon says. "It costs $80 to $90 an hour to run the equipment, so we can easily save $1,000 in a storm." Pingeon estimates that it costs $6,250 to install 220 m (720 ft) of snow fences, so it takes only a few storms to pay for the fences for a year.
The Benefits
"I'd tell anyone considering snow fences that they really do the job," says Pingeon. The benefits of snow fences include:
- Safer roads due to clearer pavement and improved visibility.
- A helping hand for plow crews trying to keep roads clear.
- Lower costs for winter maintenance.
