I woke this morning (Christmas Eve) to find that a light coating of lake-effect snow was deposited over northeast Ohio last night. We have a patio made with large bricks sitting on what I assume is a bed of sand. Rain, snow and frost all produce interesting patterns on these stones because of the properties of the stones themselves, the material used to fill the cracks and the thermal energy emitted from the house a few feet away. This morning had an extra surprise that had my kids and I scratching our heads a little bit to explain? (see last two pictures)
I am taking this picture from a large window in our family room. The outline of the patio stones is very clear. There is about 1 to 10 millimeters of space between the stones most has some moss growing in it. That moss is much colder than the surface of the stones since the stones are conducting heat from the soil below. It is the same reason that snow sticks to the grass before it does to the sidewalk.
I am taking these pictures from a large window in our family room so the bottom of this picture is very close to the house. At the same time I see the beauty in these patterns I also see money slipping out of my wallet as my house emits thermal energy melting the snow nearest the house.
You can see the patio stone pattern very clearly in the snow but what perplexed me was the pattern of snow distribution on the patio table. It is probably the science geek in me but as soon as I looked out of the window this morning I immediately asked myself, what happened to the snow on that table? Notice that there is no mound of snow below the table and no tracks to the table.
A close-up of the snow on that table. I thought maybe it was a bird that landed on the table but this doesn’t look like a birds doing and there is no noticeable accumulation of snow on the ground below. But notice that the snow is thicker on part of the table than it is anywhere else including anywhere in my yard. After a few minutes I figured it out but first I had my kids look at it and come up with ideas. They were quite perplexed but finally one of them said, what about the wind? I think that is exactly what happened. I think a wind gust came around the house and came up under the table blowing the very light snow up and folding it over onto other snow on the table. We watched for a little while and we noticed a small gust of wind that swirled up some snow on the table and that was enough to convince the kids that a larger gust could have done it.
Well, the kids got a little science lesson though I think they would rather have been on the X-box. Oh well, got to head out for some last minute shopping now with the boys. I’d rather be taking pictures:-(
Update: New years eve. More snow this morning and some new patterns appeared. Now I can see that there must be a difference in the composition or thickness of some stones in the patio. Look at how the snow has melted differently to the stones.
This last shot below is from about 30 minutes after the one was taken above. In that time more snow has melted making the pattern of the patio stones even more apparent.
Naturalis Historia 