Scotti- You are closer than you think.
Lenny- Not so much, but thanks for the chuckle and yes, still room for you and more at the Ride-In!
Tomcat-
I guess I can start out by saying that all snow settles over time, but how much the snow settles has much to do with how much air was in it when it fell (light and fluffy vs. wet and heavy) as well as the amount of new snow that falls on top of the old. The more that falls on top of the old, the more the old will get compressed and settle. By the end of the winter, the snow at the bottom of our snowpack is almost like ice.
While there are many different consistencies to system snow, the difference is even greater for LES. Early in the season when the lake is still pretty warm (40's-50's) we can have as wet and heavy a LES as you are ever going to see with any system snow. We even get lake effect rain. As the lake cools, the air temperature needed to produce the LES needs to cool accordingly. The cooler temps tend to make the snow drier and many times fluffier and by this time of the year, much of our LES is much drier and fluffier than the average system snow.
There is a thing called the snow-to-liquid ratio, which simply explains how many inches of snow fell based on an inch of moisture. Obviously not every snow event contains an inch of moisture, but you can measure the snow that fell, melt it down and come up with the liquid amount. A very wet and heavy snow may be as much as 6:1 or 8:1 (6-8 inches of snow/1 inch of moisture in the melted snow). The average system snow (not the wet and heavy type, but the type that falls with temps in the 26-30 degree range will be around 12-14:1. LES is typically around 15-20:1, but can be as high as 30:1 or even in unique instances 40:1. Once it gets to 30-40:1, it is what I call "broom snow", meaning you can literally move 5-8" of it with a push broom if you wanted to.
Probably the number one factor that determines the ratio is air temp. In general, the colder the air, the lighter and more fluffy the snow and the higher the ratio. However, when the air gets really cold (like low single digits or below), the flakes usually get very small and thus the ratio drops. Such is the case with the snow we have been getting all day. I have picked up around 4" new today, but the flakes have been very small and thus the consistency to the snow is much like that of your average system snow and if I measured, it would probably be around 13-14:1.
Another factor is the humidity level where the snowflakes are being produced. The higher the humidity, the bigger the flakes and the bigger the flakes (when the air is below around 28 degrees) the lighter and fluffier the snow.
Strong winds can actually break up the snow into smaller flakes as it falls and that lowers the ratio as well.
With all this said, I have found that over the course of a winter, our snow will settle at a rate from say 10 inches to around 3 or 4. This is due both to the fluffy variety of the LES (which makes up around 70% of our annual average snowfall) and the fact that the new stuff is compressing the old.
I am actually thankful for this settling and the fact that most of our snow is light and fluffy. I cannot even begin to imagine the work involved in trying to move around 250" (on average) of wet and heavy snow every season!
-John
PS PR1, I was typing my dissertation when you posted, so missed including you.
