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Why Does it Feel Like I am Plowing More Snow Than What is Reported Sometimes?

How come when I plow it seems like I am plowing more snow than what is reported?

This is a question I have come across many times, and this is my best attempt to answer that question. Basically, it boils down to the way people measure snow. Snow is measured multiple times each day at most official NWS reporting locations such as DIA but that can vary and these locations are typically the most accurate but only represent a single point of reference. Thus, many spotters whom are private citizens typically only measure snow once a day(but not always). Many times a person will see the snow start and then wait for it to stop then take a measurement before the snow settles or begins to melt for a good representation of a storm total snowfall. Or they will measure at the same time ea/morning. This is perfect if the storm is less than 1 day in duration and temperatures are cold enough that there is no melting. There are many cases where settling/melting occur before a spotter measures and this is often not their own fault, they may be working, or have other duties to attend to instead of observing weather. Lets throw the melting factor out and pretend that the ground is frozen to help answer this question, “How come when I plow it seems like I am plowing more snow than what is reported?” Now imagine you’re in your plow and you plowed 1” of snow off of a lot each hour for 10 hours. You must be thinking I got 10” of snow, right? Wrong, you may have technically plowed 10″ but… A spotter would not measure 10” of snow because the 2nd inch would compact on the 1st and the 3rd on the first 2 inches, etc. So, after 10 hours the spotter measures only 7” at same location. This is the compaction factor; this factor is greater when the snow is “dry and powdery” and less so when the snow is “heavy and wet” and can vary significantly during the season. The powder snow is powdery because there are more air pockets than a wet snow. In short “dry snow” will have a compaction factor greater than a “wet snow” if that makes sense. The liquid to snow ratio which is used to determine a wet/dry snow is referred to as the LSR. LSR’s can range from as little as 4-5” of snow to 1” of water to 20-30” of snow to 1” of water here in Colorado.  Wet snow IMHO is anything less than 10:1, and anything greater than 18:1 I would say is a dry snow with that middle ground being the, lets just call it “regular old snow”. 
I won’t even address the wind factor and drifting over previously cleared surfaces but this indeed makes it feel like you are plowing EVEN MORE than will be reported. Anyway, it will ALWAYS feel like you are plowing more than reported because YOU ARE, I guess that is what I am saying. But in all honesty, plow drivers are an UNDER-appreciated bunch, TYVM PLOW DRIVERS!
If you have any interest on how spotters are supposed to measure snow here is a great link with brief video:

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