Stop chilliwacks snow, one fence each

In a snow -covered winter weather, it is orange fences that make good neighbors.

Every year the city of Chilliwack installs almost 4,000 meters of snow crimes – contemporary obstacles that defend local roads against blowing blowing. Together with the city's snow removal teams, you prevent some of the most important transportaries from chilli -wack to traffic when wind and snow begin to blow.

But the physics of the fence in the weather is more complicated than you could expect. And even though chilliwack has found success with snow fences, not every Fraser Valley community with large fields uses the modest fence to prevent the snow from covering its streets.

If you drove one of the north-south-artificial roads from chilliwack in winter, you have probably seen the city's snow fences. The fences, which are placed in parallel to the street in neighboring fields, are an important part of the chilliwack strategy and are installed every year before falling the flakes.

This year the city's operating department gathered 3,900 meters of fences in more than a dozen places, including along the PST PST PST PST PST PST PST PST PST PST PST PRESTTT and EVANS Road, two of chilliwacks busy. The snow fences are used to protect streets surrounded by open fields, on which strong winds drive long snow.

The snow fences slow down the wind and can be slowed down in a controlled area instead of randomly drifting on local roads. The hope is that the fences can reduce the cost distance costs and improve the visibility of driving.

In order to set up a snow fence, chilliwack must first receive the permission of the owner in which the fence is installed. As soon as this happens, the city sends teams to build fences in the community.

It takes between two and three hours for each crew to install every fence. Chilliwack Staff put every heavy post in the ground and then falls into the removable fence on the inserts. The fences are removed from the road at a firm distance -usually between 30 and 50 times its height -so that the snow can accumulate around the fence rather than around the street.

After that, everything that remains remains until the snow arrives.

It wasn't always like that. Chilliwack began to install only in the past five years or so fences.

(The Chilliwack employees are not quite sure when the program began: An article by Chilliwack Progress in February 2019 said “The first year 2019 sounds precisely.”)

The snow fences are used in areas that have long -term problems with snow -wraps like Past Road. Snow was a problem along the past, as long as vehicles tried to navigate through the street in winter. In a newspaper article in January 1950 it was described how the residents had resorted to sled after snow shifts prevented the residents from using their vehicles for weeks. In 2006, Chilliwack Progress photographer Jenna Hauck determined a picture that tried six people to push a car out of a snow. It was finally dragged out by a passing pickup, and Chiliwack later closed the street.

The introduction of snow fences aimed to reduce the need for the crew to clear the same section of the street again and again. At about the same time, the city had started to establish more outstanding forms of snow: to plant shrubs on the side of the road on some streets to act as wind blocks and ask some farmers to leave a corn strip on the edge of their fields.

The program was a recall of some of the earliest use of snow fences that – like other elements of society – faded over time in and outside of popularity.

The first written reference to snow fences as an infrastructure was a small book, which was published in 1852 by the Norwegian roadmaster GdB Johnson. His book, which gathered sketches of the snow, which gathered around barriers such as fences, contributed to awaken an interest in the use of physical structures to prevent snow from gathering on the tracks of the railways that occur throughout North America. In the United States, a tourist leader from 1880 emphasized the rails “countless” snow fences along the tracks for the rails.

The snow fences increased in popularity when cars became more common, but later fell back from favor when the violent infrastructure overwhelmed. The physics, such as snow fences gathered snow, was poorly understood, and stronger trucks and plows seem to push simple snow snow instead.

Brute Force, however, was expensive. In 1957, BC spent more than 1% of its budget for snow removal. In a report from the time, it found that “these costs are a very serious matter, and yet public demand is today that there is no way to reduce these costs and still enable the demanding service.”

In the 1950s, Russian scientists began to research how snow fences actually worked – and how they could be more effective. At that time, snow fences were used to protect about half of the streets in Russia, said a paper, but some believed that temporary fences could collect even more snow along streets like Siberia if they were applied correctly. In 1954, the researcher AA Komarov published a formula that enabled the officials to calculate the storage capacity of a temporary snow.

The Canadian National Research Council translates the paper in 1963 and said that it would help the engineers to understand the “theoretical aspects of the problem” of snow shifts. The Americans started their own work in the physics of snow shifts at about the same time. The return of the snowfig in North America had started.

Snow fences don't work because they actually stop snow, but because they reduce the speed of the wind. The snow begins to drift when the winds reach about 15 km/h (a speed that shows a respectable but not outstanding, which shows in the Boston marathon). With increasing wind speed, even at small quantities, it can absorb more snow exponentially. (A 19 km/h wind has approximately double energy of 15 km/h.)

When the wind hits a barrier, the energy drops and the snow slows down and collects on the floor. (Physics is similar to that of how sediment moves in river systems that we have reported here.)

Snow will of course accumulate wherever the wind slows down: trenches, near trees, by buildings or on street embankments. By slowing down the wind in a certain area, fences can keep away from the streets.

How much snow a fence can collect depends on how the fence is built and how “porous” it is. A firm fence creates a big snow pile on the side on which the wind hits the fence, and on the other hand very little. A fence with gaps, on the other hand, mainly collects snow on the Lee side and not on the wind side.

A fence with more gaps can collect more snow – albeit over a longer drift area. This means that there must be enough space for the snow between the fence and the road to collect, otherwise the crews are directly back where they started. Drifts can be more than 10 -longer than the fence is tall, which is why chilliwack puts its fences away from the street.

Chilliwack is checked every year its list of “strategic locations” to determine where it should add more fences. The city has added around 150 m fences to its program every year.

It is not the only community in the Fraser Valley that uses snow fences. The Kent district also uses snow fences at four locations in the community: Tranmer Road, McDonald Road, Cameron Road and McCartney RD.

Abbotsford, on the other hand, used, although you also have open fields and stormy weather in Sumas Prairie, not a systematic way of snow fences. It uses heavy devices such as Grader and plow and crews that work during the storms in 12-hour layers to blow snow in the Sumas Prairie, which, according to the city, is too large to deal with fences.

“In order to properly use and implement a snow fencing program, large areas of area would be necessary that the city does not have,” wrote a spokesman for Abbotsford in an email to the current one. “A snow fencing program is not considered necessary at this point.”

Chilliwack does not have the country in which it brings its fences – a spokesman who contacts the owners of the property owner there a year to maintain permission and to negotiate locations, installation and cleanup. And these owners – many of whom live near the streets protected by the snow fences – seek to voluntarily report their country.

“The majority of real estate owners are happy to help support the program because they recognize the advantages for the community,” said Chiliwack spokesman in an e -mail.