Mn/DOT Agreement No. 74708

"Climatological Characterization of Snowfall
and Snowdrift in Minnesota"

Summary Report for Task 4 of Project

Task 4: Development of web site that hosts an interactive climatological database and associated products for evaluation and design of living snow fences

Duration: 24 months

Deliverable: Directions for access and use of the web site


Access to Web Site

  Database Browsing
  Climate Summary Browsing
  Tabler Parameters and Case Studies


Comment: This task report provides access and navigation instructions for use of the web site developed under this contract. The web site hosts all of the deliverable information generated by earlier work on the project, including the following: the interactive climatological database (described in task 1); summary tables, graphics and maps of relevant parameters (described in task 2); and model calculations associated with the Tabler (1994) methodologies, field assessment and case studies for the deployment of living snow fences (described in task 3). Because this project depends upon the use of the statewide climatological database and associated software, all of which are maintained by the DNR-Minnesota State Climatology Office, their existing web site was modified to host this information. It is available 24 hours per day, 7 days per week via the Internet, and further it is updated annually with new climatic data. Therefore, the database is dynamic and will grow over time. However, summary products such as maps and tables, as well as model calculations and case studies reflect analysis of the data with state-of-the-art knowledge through the year 2001. Into the future, with many additional years of data incorporated into the climatological database, Mn/DOT may choose to update these summary products to better represent the full historical record and advances in the knowledge base for the design of living snow fences. The web site is available to the public without restriction, except as expressed in the disclaimer statements that follow.

Disclaimer: The Minnesota Department of Transportation (Mn/DOT), in cooperation with the University of Minnesota (UMN) and the Minnesota Department of Natural Resources State Climatology Office (SCO) provide these data, and the associated maps, tables, and analyses for informational purposes only. As with most government services, these data exist in the public domain, but users are encouraged to pay special attention to the conditions and provisions under which the data were collected, as there were some variations in method of observation. The user assumes the entire risk related to use of this database. Data are provided on an "as is" basis and Mn/DOT, UMN, and the SCO disclaims any and all warranties, whether express or implied, including (without limitation) any implied warranties of merchantability or fitness for a particular purpose. In no event will Mn/DOT, UMN, or the SCO be liable to users or to any third party for any direct, indirect, incidental, consequential, special or exemplary damages or lost profit resulting from any use or misuse of this data.

Access: Interaction with the web site is possible with any Internet browser. The home page can be found at The interactive climatological database can be found under the hypertext link for Historical Climate Data/Summaries. This will link to the revised URL

Database Browsing: The first option shown, Interactively Retrieve Daily/Monthly Climate Data provides access to a geographic locator under the URL From this point the user is required to select a location in the state of Minnesota, therefore the set location window should be clicked. A map will be displayed from which the user may position the cursor to any location and click. The screen will refresh and show the attributes of the location selected, including UTM coordinates, latitude and longitude, as well as township, range and section number. If the user wants more detailed definition, the zoom in button can be used to show finer scale of county boundaries as well as individual climate stations.

Once satisfied with location selection, the user selects the bar for done/return. The screen returns to the previous menu, showing the geographic attributes and the station selected by name. Users may pull down the window for station name and select from a list of possible locations to represent the geographic area chosen. This may be useful when only certain stations represent the time period or variables of interest. Users can cross-reference an inventory of time periods and climate variables by examining the table (click).

Once a location has been specified, the next step is identifying the years of data needed. This can be done by clicking on the pull-down menu opposite the word years.

The time series may range from a single year to over 100 years of data. Users should be aware that long time series may take several minutes to retrieve and therefore selection of shorter times series (30 years or less) is encouraged. Once the time series has been selected, the user may specify the variables of interest from the list shown. Precipitation, temperature (including daily maximum and minimum), and snowfall may individually be checked or checked in combinations. Default conditions for retrieving a time series of data (days, weeks, months, or years) specify no more than three missing days. If this condition is not met, then data from the selected location will not be retrieved. However, if the user wants to specify a different tolerance for missing data, the value in the window for missing data may be changed.

Once these selections have been made, the data retrieval will commence upon clicking the monthly or daily data value window at the bottom of the page (get monthly or get daily). Retrieval of the data will be interactive and therefore take some time to process. Short times series of single climatic variables will only take seconds, while longer time series of multiple variables may take minutes depending on the speed of the Internet connection.

There is a clear distinction between retrieving data for a single location and retrieving data for a landscape location based on the closest climate station. The user may stipulate the use of only a single location by checking the box retrieve only this station. The data processing will only consider this single location and give all available variables for the time period specified. However, if this box is not checked, the data processing will essentially provide a time series of variables from the nearest available climate station to the landscape position selected on the map. Such a time series may indeed represent a composite of climate data taken from several locations near the landscape position selected if the nearest station available does not have a complete data set. The data array will thus represent the best-estimated climate variables for the site selected and not necessarily a complete time series from one individual climate station.

Climate Summary Browsing: Summary tables, graphics, and mapped data of important climatic variables can be browsed utilizing the Analysis of Snow Climatology web site. This can be accessed using the URL:

Users can view a list of all summaries and images by category: snow accumulation season, snowfall frequencies, snow water equivalent and wind analysis. Under the first category, snow accumulation season (SAS), the user can click on onset date or end date and the map will appear to the right of the navigation bar. A larger version of the map can be viewed by clicking on the image and will appear in a separate window. If more information about development of the map is needed, the user may click on the text, How was this map developed? These steps can be done for all of the products on this site.

Under the snowfall frequencies category, for the mean snowfall option the user can determine the length of season to be used, either annual, seasonal or SAS. For snow fence design purposes, the SAS option is most appropriate. Once the length of season is chosen, thumbnail views of the maps are presented and the user can view the product by clicking on the desired image. In addition, four options are given representing four different time scales. The products representing the most recent 30 years, 1971 - 2000, are most appropriate to use for snow fence design purposes. Similar procedures can be used for viewing percentile ranking and snowfall ranking products. Snow water equivalent products can be viewed by clicking the mean monthly text under snow water equivalent. Thumbnail maps appear once the text is clicked and the user can choose which product to view by clicking on the map for a larger image.

To view wind analysis products, the user can click on data by station under the wind analysis category. A map of Minnesota will appear in which the locations of the available stations are displayed. The user can click on the location on the map, or the station name, which is listed in alphabetical order below the map. Once the desired station is clicked, three products are shown, wind rose figures for October through March are given first, followed by modal direction and potential snow transport (delimited by wind speed class and direction class).

Mapped and graphic details are best viewed and interpreted in color, so printing out the black and white version is discouraged because of the loss of detail. Miscellaneous information is given at the bottom of the navigation bar and includes a clickable Mn/DOT district boundary map, disclaimer and reference page. If further information is desired concerning development of these products, the user can consult the Task 2 summary report.

Tabler Parameters and Case Studies Browsing: The Tabler methods and parameters for the design of a living snow fence can be browsed from the Case Study portion of the web site. The first page of the Case Study analysis includes an image and short description of each of the three locations studied in southern Minnesota. By clicking on the location name above the photo, a new window will appear outlining the necessary steps to design a living snow fence, as described by Tabler (1994). The user can navigate through the steps by using the back and next buttons at the bottom of the middle section of the window. The left side tracks the users progress through the steps while the middle section gives a description of the current step. Included in the right-hand portion of the window are any maps, figures or tables specific to the current step in the design process. The conclusion section of the case study compares the studied design and observed 2000-01 snow storage with modeled values. The user is urged to follow the design steps in the order they appear, however, text on the left side of the window may be clicked to go directly to a particular step.

Clicking on any text in red provides the user with a more detailed description of the topic. Users may wish to print some of the case study material for more thorough evaluation. Use of this web site material in conjunction with the guidebook produced by Gullickson (1999) will provide users with a state-of-the-art working knowledge and database for designing a living snow fence. The user may wish to consult the Task 3 summary report for further information regarding calculation of the Tabler parameters for Minnesota as well as an investigation of the agricultural implications for each case study location.


(1)   Tabler, Ronald D., "Design Guidelines for Control of Blowing and Drifting Snow", SHRP-H-381, Strategic Highway Research Program, National Research Council, Washington, D.C., 1994.

(2)   Gullickson, Dan et al. 1999. Catching the Snow with Living Snow Fences. Mn/DOT Office of Environmental Services and University of Minnesota Extension Service (MI-7311-S) 140 pp.