scholarly journals Design Criteria and Location of Snow Fences

1985 ◽  
Vol 6 ◽  
pp. 68-70 ◽  
Author(s):  
Harald Norem
Keyword(s):  
Minimum Distance ◽  
Storage Capacity ◽  
Windward Side ◽  
Design Criteria ◽  
Total Density ◽  
Design Considerations ◽  
Drifting Snow ◽  
Snow Fence ◽  
Snow Model ◽  
Snow Fences

The paper describes experience gained in Norway regarding the design criteria and use in practice of snow fences. The paper is based on theoretical studies on drifting snow, model experiments and experience accumulated through practical consulting work. Snow fence design is a compromise between the storage capacity and minimization of dimensioning forces. Design considerations include fence height H, total snow fence density, and the gap between ground and fence. A gap of 0.15H - 0.2H and a total density of 45% are usually recommended. On ridge crests the gap can be reduced to 0.1H and in areas where snow depths exceed 2.0 m, it can be increased to 0.3H. In such cases the fence density should be varied such that the total density, including the gap, will remain near 45%. The height of the snow fences should be kept within 3.5 -4.5 m and the snow fences should be erected on the windward side of obstacles that create snowdrifts. The minimum distance from fence to road should not be less than 15H; in certain circumstances in coastal climate, this can be reduced to 10H.

scholarly journals Design Criteria and Location of Snow Fences

1985 ◽  
Vol 6 ◽  
pp. 68-70
Author(s):  
Harald Norem
Keyword(s):  
Minimum Distance ◽  
Storage Capacity ◽  
Windward Side ◽  
Design Criteria ◽  
Total Density ◽  
Design Considerations ◽  
Drifting Snow ◽  
Snow Fence ◽  
Snow Model ◽  
Snow Fences

The paper describes experience gained in Norway regarding the design criteria and use in practice of snow fences. The paper is based on theoretical studies on drifting snow, model experiments and experience accumulated through practical consulting work.Snow fence design is a compromise between the storage capacity and minimization of dimensioning forces. Design considerations include fence height H, total snow fence density, and the gap between ground and fence. A gap of 0.15H - 0.2H and a total density of 45% are usually recommended. On ridge crests the gap can be reduced to 0.1H and in areas where snow depths exceed 2.0 m, it can be increased to 0.3H. In such cases the fence density should be varied such that the total density, including the gap, will remain near 45%. The height of the snow fences should be kept within 3.5 -4.5 m and the snow fences should be erected on the windward side of obstacles that create snowdrifts. The minimum distance from fence to road should not be less than 15H; in certain circumstances in coastal climate, this can be reduced to 10H.

scholarly journals Field experiments on “living” snow fences

1998 ◽  
Vol 26 ◽  
pp. 217-220 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Pierre Mullenbach
Keyword(s):  
Field Experiments ◽  
Snow Accumulation ◽  
Real Problem ◽  
Effective Height ◽  
Natural Plant ◽  
Drifting Snow ◽  
Snow Fence ◽  
Limited Scale ◽  
Living Fences ◽  
Snow Fences

In Franee, drifting snow is generally controlled using artificial snow fences. Living snow fences are not a new concept but they have only been used on a limited scale. Research directly related to natural plant barriers is limited. We therefore decided to study the behaviour of species that would survive and grow satisfactorily in the French Alps.In the first experiment, we compared the storage capacity of several different kinds of living fences consisting of pruned spruces, unpruned spruces and sorbs.Field observations during the winter of 1995-96 proved that deciduous trees such as sorbs are effective, and that pruning the lower 50 cm is not effective at the end of the season because of the weight of snow on low branches.However, the use of natural plant barriers has disadvantages: a living snow fence takes time to reach an effective height and is difficult to establish on windy sites at a high altitude. This is a real problem. Therefore, in a second experiment, we studied the death rate of larches planted behind a fence. We noticed that the snow fence had several effects, snow accumulation (until the planted trees grew up) and protection of the planted trees.

Use of Snow Fences to Reduce the Impacts of Snowdrifts on Highways: Renewed Perspective

2017 ◽  
Vol 2613 (1) ◽  
pp. 45-51 ◽  
Author(s):  
Sen Du ◽  
John Petrie ◽  
Xianming Shi
Keyword(s):  
Road Safety ◽  
Right Of Way ◽  
Drifting Snow ◽  
Snow Fence ◽  
Survey Results ◽  
Snow Fences ◽  
The Right ◽  
Survey Responses ◽  
Almost All ◽  
Departments Of Transportation

In northern climates, snow fences are usually established in or beyond the right-of-way to eliminate blowing and drifting snow on roadways and thus improve road safety. To make snow fences more effective on highways and provide guidelines for the departments of transportation siting the fences, this work reviews the literature as well as survey responses from practitioners in northern states. This review combines information obtained from the resources to detail several aspects of snow fence use, including history, design protocols, siting policies, benefits, challenges, and numerical modeling. Particular attention is paid to living snow fences as an alternative to traditional structural snow fences. The survey results show that almost all the responding agencies have launched snow fence programs, which have various design and siting protocols that depend on the specific conditions.

scholarly journals Living snow fences for protection of roads: case study crest Čestobrodica

2019 ◽  
Vol 65 (4) ◽  
pp. 17-22
Author(s):  
Mladen Marković ◽  
Sara Lukić ◽  
Aleksandar Baumgertel ◽  
Marko Maslaković
Keyword(s):  
Traffic Safety ◽  
Storage Capacity ◽  
Road Maintenance ◽  
The Road ◽  
Snow Storage ◽  
Road Section ◽  
Snow Fence ◽  
Downwind Side ◽  
On The Road ◽  
Snow Fences

Snowdrifts caused by wind gusts reduce visibility on the road which endangers traffic safety, increases travel time and road maintenance costs. Based on previous experience and research it has been proven that living snow fence is an economical, ecological and efficient solution for protection of roads from snowdrifts. Living snow fences with their above-ground part, reduce the wind speed, act as a mechanical barrier for the snow and accumulate a certain amount of snow. This study presented use and efficiency of living snow fence in controlling snowdrifts on the road section Paraćin-Zaječar, locality – crest Čestobrodica. Analysis of environmental conditions, which are resented main endangering factor for snowdrifts, included the determination of indicators of possibility of snowdrifts: snowfall water equivalent (Swe), snow transport (Q) and ability of living snow fence to prevent snowdrifts: snow storage capacity of the fance (Qc). Snow storage capacity for living snow fence is analyzed for ten year period. Using equation for estimation of length of snowdrifts on downwind side of fance, a change in length of snowdrifts during the analyzed period are determin, and the efficiency of living snow fence in protection of the road from snowdrifts with increasing age.The results of this study represent a contribution to using living snow fence in solving the problem of roads protection from snowdrifts and increasing traffic safety during winter conditions.

scholarly journals Field experiments on “living” snow fences

1998 ◽  
Vol 26 ◽  
pp. 217-220 ◽  
Author(s):  
Florence Naaim-Bouvet ◽  
Pierre Mullenbach
Keyword(s):  
Field Experiments ◽  
Snow Accumulation ◽  
Real Problem ◽  
Effective Height ◽  
Natural Plant ◽  
Drifting Snow ◽  
Snow Fence ◽  
Limited Scale ◽  
Living Fences ◽  
Snow Fences

In Franee, drifting snow is generally controlled using artificial snow fences. Living snow fences are not a new concept but they have only been used on a limited scale. Research directly related to natural plant barriers is limited. We therefore decided to study the behaviour of species that would survive and grow satisfactorily in the French Alps.In the first experiment, we compared the storage capacity of several different kinds of living fences consisting of pruned spruces, unpruned spruces and sorbs.Field observations during the winter of 1995-96 proved that deciduous trees such as sorbs are effective, and that pruning the lower 50 cm is not effective at the end of the season because of the weight of snow on low branches.However, the use of natural plant barriers has disadvantages: a living snow fence takes time to reach an effective height and is difficult to establish on windy sites at a high altitude. This is a real problem. Therefore, in a second experiment, we studied the death rate of larches planted behind a fence. We noticed that the snow fence had several effects, snow accumulation (until the planted trees grew up) and protection of the planted trees.

scholarly journals The effect of wind direction on drift control by snow fences

2001 ◽  
Vol 32 ◽  
pp. 159-162 ◽  
Author(s):  
Yukari Takeuchi ◽  
Shun’ichi Kobayashi ◽  
Takeshi Sato ◽  
Kaoru Izumi ◽  
Kenji Kosugi ◽  
...  
Keyword(s):  
Wind Tunnel ◽  
Wind Velocity ◽  
Wind Direction ◽  
The Other ◽  
First Case ◽  
Snow Fence ◽  
Snow Fences ◽  
Set Up ◽  
Cold Wind ◽  
Drift Control

AbstractSnowdrifting processes and the wind-velocity profiles around a collector and a blower snow fence were investigated in a cold wind tunnel. The purpose was to ascertain the effect of wind direction on drift control by snow fences. Three different cases were studied for both types of snow fence, and the resultant snowdrifts were compared. In the first case, the snow fence was perpendicular to the wind direction. In the second and third cases, it was tilted by 30° and 45°. When the collector snow fence was tilted, the amounts of snowdrift were much less than when the fence was perpendicular to the wind direction, because the area with low wind velocity was reduced to half behind the tilted fence. On the other hand, the blowing effect of the blower snow fence increased when it was set up at an angle to the wind direction. It is necessary to investigate the position where the blown snow is deposited by the tilted blower snow fence.

scholarly journals Numerical simulation of drifting snow: erosion and deposition models

1998 ◽  
Vol 26 ◽  
pp. 191-196 ◽  
Author(s):  
Mohamed Naaim ◽  
Florence Naaim-Bouvet ◽  
Hugo Martinez
Keyword(s):  
Mass Exchange ◽  
Field Measurements ◽  
Numerical Results ◽  
Back Reaction ◽  
Erosion And Deposition ◽  
Deposition Model ◽  
Drifting Snow ◽  
Snow Fence ◽  
Flow Turbulence ◽  
Deposition Models

Earlier works on numerical modelling are analysed. Anderson and Haff (1991) proposed a model using the “splash” function which was defined for cohesionless sand. The Uematsu and others (1989, 1991) and Liston and others (1993,1994) approaches are based on fluid-mechanics conservation laws where the snow is transported and diffused by the air flow. These models consider the saltation layer as a boundary condition.For the flow, and for the suspension, we adopt the same model as that of Uematsu and Liston. For mass exchange between the flow and snow surface, we have developed an erosion–deposition model where mass exchange is defined in relation to flow turbulence, threshold-friction velocity and snow concentration. Our snow-erosion model was calibrated using Takeuchi's(1980) field measurements. The deposition model was tested by comparing numerical results with wind-tunnel ones, for sawdust-accumulation windward and leeward of a solid snow fence with a bottom gap. The numerical results obtained are close to the experimental results. The main results of the various sensitivity experiments are: the leeward accumulation is very sensitive to the ratio (u*/u*t) (it appears for (u*/u*t) close to 1 and disappears for (u*/u*t) > 1.2), the global accumulation produced by the fence increases as (u*/u*t) decreases and the back reaction of particles on turbulence extends slightly the windward accumulation.

Investigating Safety Effectiveness of Wyoming Snow Fence Installations Along a Rural Mountainous Freeway

2017 ◽  
Vol 2613 (1) ◽  
pp. 8-15 ◽  
Author(s):  
Thomas Peel ◽  
Mohamed Ahmed ◽  
Noriaki Ohara
Keyword(s):  
Empirical Bayes ◽  
Winter Season ◽  
High Rate ◽  
Control Surface ◽  
Blowing Snow ◽  
Snow Fence ◽  
Adverse Weather ◽  
Safety Effectiveness ◽  
State And Local ◽  
Snow Fences

Drifting and blowing snow is a problematic and dangerous aspect of Interstate travel in the state of Wyoming. The control of snow and the maintenance of roadways is an essential and significant task for many state and local agencies. Many significant factors—such as vehicle control, surface conditions, and visibility—can be affected by hazardous winter weather. In areas such as the inspected 19-mi section of Interstate 80, snow fences have become a common and practical method of mitigating the problems caused by large quantities of snow near or on the traveled way. Wyoming deals with a high rate of adverse weather–related crashes during the winter season. Naive before–after analyses of snow fence installations have historically indicated a slight decrease in such crashes. In this study, the safety effectiveness of snow fence installations was investigated; more rigorous quantitative-based approaches were used and included a before–after analysis with empirical Bayes—in which Wyoming-specific safety performance functions were used—and odds ratio analyses. Crash modification factors were estimated for various crash types and severity levels. The results from this study indicate that the installation of snow fences contributes to a significant increase in the safety effectiveness of Interstate use during the winter. Specifically, it was found that during adverse weather conditions, snow fences decreased total crashes and fatal and injury crashes by about 25% and 62%, respectively.

scholarly journals The impacts of moisture transport on drifting snow sublimation in the saltation layer

2016 ◽  
Vol 16 (12) ◽  
pp. 7523-7529 ◽  
Author(s):  
Ning Huang ◽  
Xiaoqing Dai ◽  
Jie Zhang
Keyword(s):  
Moisture Transport ◽  
Global Climate ◽  
Balance Equations ◽  
Feedback Effects ◽  
Drifting Snow ◽  
Moisture Advection ◽  
Cooling Effects ◽  
Snow Model ◽  
Heat And Moisture ◽  
The Antarctic

Abstract. Drifting snow sublimation (DSS) is an important physical process related to moisture and heat transfer that happens in the atmospheric boundary layer, which is of glaciological and hydrological importance. It is also essential in order to understand the mass balance of the Antarctic ice sheets and the global climate system. Previous studies mainly focused on the DSS of suspended snow and ignored that in the saltation layer. Here, a drifting snow model combined with balance equations for heat and moisture is established to simulate the physical DSS process in the saltation layer. The simulated results show that DSS can strongly increase humidity and cooling effects, which in turn can significantly reduce DSS in the saltation layer. However, effective moisture transport can dramatically weaken the feedback effects. Due to moisture advection, DSS rate in the saltation layer can be several orders of magnitude greater than that of the suspended particles. Thus, DSS in the saltation layer has an important influence on the distribution and mass–energy balance of snow cover.

scholarly journals Design considerations for a large-scale image-based text search engine in historical manuscript collections

2016 ◽  
Vol 58 (2) ◽  
Author(s):  
Lambert Schomaker
Keyword(s):  
High Performance Computing ◽  
Search Engine ◽  
High Performance ◽  
Large Scale ◽  
Storage Capacity ◽  
Text Search ◽  
Design Considerations ◽  
File Access ◽  
Manuscript Collections ◽  
Performance Computing

AbstractThis article gives an overview of design considerations for a handwriting search engine based on pattern recognition and high-performance computing, “Monk”. In order to satisfy multiple and often conflicting technological requirements, an architecture is used which heavily relies on high-performance computing, interactivity, and a Posix file-access model for the scientific programmers. The resulting system is able to handle billions of image files, in the order of petabytes of storage capacity, with a single mount point. Monk is operational since the year 2009.

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