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Snow and Ice Control Consultant
Snow Removal Equipment Expert Trainer
Snow and Ice Contractor Equipment Maintenance Consultant
Solving Freezing Rain
Effective Treatment Plans Should Begin with Contract and Level of Service.
by Dale Keep, Consultant and Trainer to Snow Removal Contractors Across North America
Different events can impact how contractors use labor, equipment and materials (LEM) to effectively and
efficiently deal with the storm. This is especially true when freezing rain is involved. We all know that some
storm events are tougher to handle than others, but a freezing rainstorm of even medium intensity and duration
has to be the toughest. Generally, freezing rainstorm events represent receiving water over a short period of time
and quickly occurring ice buildup. Because of these storm characteristics, applications of most any deicer and/or
grit generally are rendered ineffective very quickly. To address how to best manger or approach a storm, one
must first look at the contract level of service (LOS).
Contract and LOS
How to best manage LEM is easy on a high level. It’s simple – do the right thing, at the right time, in the right
way and in the right quantity. Nothing to it. But one major detail is missing – what are you trying to accomplish?
Is the goal to use minimal deicers? Keep the pavement bare and wet at all times? Bare and wet by 7 am? Each goal
as defined in the contract can demand a different approach to best manage LEM to accomplish it. The only way to
determine how to best manage LEM when a freezing rainstorm is coming is to have a plan in mind before or as
soon as it starts. The customers’ expectations or service goals should be clearly expressed in the LOS portion of
the contract. I’ve said before, do not sign a contract until you have fully read and understand it. Does the contract
address “what if” scenarios like a long-duration heavy buildup of freezing rain? In reality, with a storm of this
type, most likely little can be done until it is over. With freezing rain, the answer is probably not as much
technical as it is legal. What does the contract say? What do you agree to do? Do you have any options, and if you
do something wise technically or realistically speaking, what risks are you taking legally?
Freezing Rain
Freezing rain is rain that hits a surface with a temperature below freezing, causing the formation of ice since the
rain freezes shortly after contact. Storms range in severity from light to severe. The real difference between them
for the sake of this article is the amount of ice created by the event. For example, assume an ice storm such as the
one occurred in northern Idaho, Jan. 1-3, 1961. This storm set a record for thickest recorded ice accumulation from
a single storm in the United States, at up to 8 inches. Historical weather data reveals that a combination of fog,
sporadic freezing rain and subfreezing surface temperatures led to the heavier ice accretions. Bear in mind that
ice created by freezing rain at a depth as low as 0.012 inches deep is just as slick as created by freezing rain at a
depth of 0.25 inches or more, even though the 0.25 is nearly 21 times as much ice and would require nearly 21
times as much deicer to melt it. Also note that the “thin ice” can actually be more dangerous since it can be
invisible or appear wet on many surfaces. For this article, the terms light, medium and heavy are used as the three
types of freezing rainstorms for comparison. Information presented is from a technical winter operations
standpoint only.
Light
The term “light” represents a small amount of moisture predicted and received. The ice created is very thin yet
dangerous but normally melts easily since temperatures during freezing rain events are typically favorable for
better deicer performance. General treatment steps:
1. Anti-ice ahead of the storm. With a light storm forecasted, the application rate should be enough to keep
areas free of ice during the event.
2. Monitor and reapply as necessary.
3. Remember that after the event passes, clearing skies and colder temperatures may follow. Under such
conditions, a deicer reapplication may be required to prevent refreeze.
Medium
Medium is between light and heavy in moisture forecasted and received, and the depth of ice created. This can be
the most difficult freezing rainstorm to manage but the easiest to write about. The answer to the correct approach
to this storm is largely based on your operations and contract specifics. By considering these two things, you can
determine if it is a light or heavy storm. Suggested treatment steps:
1. Review the weather forecast and LEM inventory.
2. Decide your approach (treatment as a light or heavy storm).
3. Anti-ice ahead of the storm, noting the surface temperature at the time of application. The application rate
should be small. The goal is to have something under the ice when the storm ends.
4. Review new forecasts, your operations and results achieved often to see if you need to change your
approach. Be realistic and flexible.
5. Follow the general steps for either the light or heavy storm events as appropriate.
Heavy
“Heavy” means a large amount of moisture predicted and received. Obviously the ice created in a storm of this
magnitude is not going to be invisible or thin, but it is going to be very dangerous. With thick ice, its removal
with deicer melting alone is probably not the answer. Suggested treatment steps:
1. Accept the fact that with a storm of heavy magnitude it is not going to be possible to stay ahead of it.
Trying to do so often means cleaning out the salt supply and then not having any deicer when then storm
ends.
2. Anti-ice ahead of the storm, noting the surface temperature at the time of application. The application rate
should be small since the goal is to have deicer residual under the ice when the storm ends.
3. Now for the hardest step: Do nothing until the storm is over.
4. After the storm has subsided, apply deicer. The goal is to penetrate the ice and get the solid deicer to the
bottom to mix with the residual from the earlier application and break the bond.
5. Plow as much as possible and reapply small amounts of deicer as necessary to remove the remainder.
6. Follow up and reapply as necessary, understanding that after the event passes, clearing and colder
temperatures may occur, and a reapplication may be necessary to prevent refreeze.
Conclusion
In any storm event, especially severe ones such as freezing rain, contract terms, LOS, customer expectations,
reality and legal risks all must be considered when determining the best approach. Only you and your team can
decide how to approach each storm, but it is imperative that these extreme storms and or temperatures be
addressed with the customer before the contract is signed.