Matching Game

Winter storms take on a variety of different forms. Whether it’s ice storms, thick powder, slush, blinding blizzards, or a mix of conditions, our goal must be the same – clear surfaces fast. However, not all deicers are effective in all storm scenarios. Let’s explore how to choose a pavement treatment product based on storm conditions.

Step 1: Use Reliable Weather Forecasting

According to the Western Transportation Institute (WTI), snow fighting crews using reliable weather forecasting experience are:

• More efficient use of manhours, less overtime, shorter work cycles
• More timely snow fighting response, including pre-treatments
• More responsible deicer product usage, which is better for drivers, budgets, the environment, and infrastructure.

There are a lot of weather forecasting apps available to snow professionals, and many of them rely on data from the National Oceanic and Atmospheric Administration (NOAA). NOAA’s Weather Prediction Center has a selection of forecast tools snow professionals can utilize to see what they are up against and plan their strategic storm response plan.

Step 2: Combine Weather and Road Data

Atmospheric data is only a piece of the puzzle. Effective snow fighting responses need an understanding of both weather and pavement conditions. Data from a Road Weather Information System (RWIS) can help crews read “real-time” conditions on the ground. RWIS is a centralized hub that collects road sensor readings. This data is combined with weather data to create a “nowcast” of conditions in a specified area. According to WTI: “the use of RWIS technologies can improve the efficiency and effectiveness as well as reduce the costs of highway winter maintenance practices.”

Here are some of the real time environmental data snow professionals should monitor throughout a snow-and-ice event:

• Air temperatures
• Wind speed and direction
• Precipitation type and amount
• Pavement temperatures
• Pavement conditions
Micro-climate data – for example, large water sources near surfaces, pavement elevations, perma-shade, and snow fence locations, to name a few.

Step 3: Select The Best Treatments

When it comes to choosing a pavement treatment, it is important to plan and not just react. Here are some general guidelines to consider when choosing which treatment to use. It’s important to note that some markets utilize aggregates – such as sand and gravel. These are not deicers or anti-icers because they do not lower the freezing temperature of ice and snow.

If you follow reliable storm forecasts, crews can deploy anti-icing/pretreatments before snow even begins to fall. A pre-treatment of liquid anti-icers or light applications of solid deicers can effectively prevent snow from bonding to the pavement to begin with. Best used before all ice storms, prior to events at night, and before forecasts of heavy precipitation rates.

Not all deicing ingredients can work efficiently at all temperatures. Remember, air temperatures and pavement temperatures differ most of the time; it is important to take both into consideration.

Temperature Ranges of Over 20° F. Anti-icers or solid deicers that contain sodium chloride, potassium chloride, calcium chloride, or magnesium chloride

Temperature Ranges of Under 20° F. Anti-icers or solid deicers that contain calcium chloride and/or magnesium chloride

When storm temps fluctuate above and below 20° F. Anti-icers or solid deicers that contain complex chlorides, so they don’t lose efficiency as temperatures rise or fall

Heavy Snowfall. For storms with heavy snow precipitation rates, use solid, granular deicers with variable gradation, or those containing some granules large enough to penetrate to the road surface and begin brining. Do not use lightweight, round pellets that have a hard time penetrating to surfaces. Avoid using liquid anti-icing treatments after heavy snow accumulation.

Windy Conditions. Applying certain pavement treatments during high wind events is counterproductive. Driving winds can prevent some products from reaching the road before they can start working. Consider using pre-wet granular deicers to reduce product waste during high winds. Likewise, reconsider using anti-icing treatments during high winds, and avoid round pellets.

Brooke Loeffler blogs about salt and deicing issues for EnviroTech Services.