Dale Keep

The winter of 2007-08 was a lesson in how the weather can cause shortages of materials, particularly road salt. Extended periods of above-average snowfall, freezing rain (in areas where it is uncommon), and associated ice and compacted snow put extreme pressure on chemical inventories. It also tested the resupply system and its strategies. Now is the time to look back at the winter's events, learn from them and develop strategies to deal with future shortage situations.

Weather intelligence
Look at historical data for each storm event. Compare the details of the storm event with the amount of salt used. Look at all applications associated with each event. Is it possible that some applications could have been greatly reduced or eliminated without affecting overall results? A key place to look is at temperatures at the time of the applications. Of particular importance is pavement surface temperature.

Pavement surface temperature is often much warmer than air temperature. Recall a sunny cold day with water on the asphalt in areas where salt was not applied? Why? Because even though the air temperature was cold, the pavement surface temperature was above the freeze point. Using pavement surface temperatures, and anticipating whether they will rise or fall—based on forecasts and time of day—can greatly reduce overall chemical use. Using less deicer chemical does not mean reducing level of service.

While level of service (contract) requirements is generally the basis for actions taken during a storm event, there are times when continuous bare surface is not reasonable, cost effective or even possible. During times of very low temperatures, the use of large amounts of salt is very ineffective, costly and reduces inventory quickly. During times of extreme cold, the use of salt pre-wet with a high performance cold weather product will reduce overall salt use and deliver the needed results. Keep in mind that at colder temperatures, the amount of deicer required to melt a given amount of ice goes up significantly.

Snowfall intensity (inches per hour of accumulation) also has a significant effect on deicer use—particularly if the contract requires bare pavement with no consideration for the fact that, at times, Mother Nature is going to win. Attempting to maintain bare pavement with repeat salt applications during high intensity, long-duration storms is not only a bad way to address the storm but also results in heavy chemical use and overuse. Sometimes it is best to accept that it is impossible to keep up during the storm event and attack with intensive plowing. When the storm is over and plowing completed, then use deicers to obtain the required level of service. This approach, though not popular with some customers, is realistic during many storm events and can greatly reduce salt use.

Deicer-saving strategies

Plowing strategies, and the timing and rate of deicer applications have a significant effect on overall deicer consumption for any storm event. Some strategies to consider include:

• Pre-treatment or anti-icing Pre-treating the surface with a liquid, or ideally, a pre-wet solid if solids are to be used, just before the start of snowfall will improve plowing results. This, in turn, will reduce the quantity of deicers needed at the end of the storm for final cleanup.
• Pre-wetting salt Pre-wetting salt with a high-performance liquid deicer enhances the performance of the salt, especially at colder temperatures, and jumpstarts the process of turning the salt to brine. This strategy provides the active ingredients necessary for melting and makes overall deicer use more efficient.
• Aggressive plowing Plowing is very often the best way to remove snow and ice from the pavement surface. Coordinate plowing with deicer applications so the deicer is not plowed off before it can work, which reduces salt use. All too often, this very thing happens. The misuse of chemicals and/or plows causing excessive salt use can too often be observed. If this misuse were reduced or eliminated, overall salt use would be reduced.