Can anyone give me a Scientific explanation for the way snow neatly accumulates on railings ?

Well, gravity makes it fall from the sky. It collects as long as it can hang together, but there comes a point at which it falls off the sides.

The Vulcan Science Council has determined that ice crystals, due to their inherent structure, will interlock with each other and thus create a mass with a certain consistency and integrity.

Increased surface area of the railing makes the wood or metal colder and then keep the snow frozen there longer.

Well, I’ll make some educated guesses:

(1) snow accumulates gradually one flake at a time, each gently settling atop the accumulation without mechanically disturbing the pile below too much
(2) snow is usually somewhat sticky, each flake adhering to its neighbors to varying degrees
(3) the rate of snowfall (flakes per square cm. per sec.) is fairly constant over the small extent of the railing (a few feet?).
*(4)*Any change in snowfall rate over time will equally affect the entire extent of the railing.
(5) the railing is straight, smooth, and all one width— another set of constants over the extent of the railing.
(6) wind is probably an important factor, different each time it snows. Wind might not be constant across the whole railing if parts of it are more sheltered than others, i.e., broken symmetry.

So snow piling on railings might have a steep angle of repose which forms a constant cross-section along the length of the railing. The cross-section might be triangular, semi-circular, inverted catenary? or some other geometrically interesting curve, with non-linear features creating, perhaps, aperiodic blobs or defects in spots where wind is gusting. Nature is a great artist…

@philosopher Is your railing round or square?

@gasman
It is square. What intrigues me is how odd the top of my deck looks. It looks like it was sculptured.
I wish I could post a picture.
Thanks for your explanation.

@philosopher ; take a photo and put it on you avatar…

My neighbor has a trampoline and the curve of the top mirrors the curve underneath. It could be a lens. I bet it weighs many pounds.

The answer is simple: the railing freezes and the snowflakes stick together on the frozen metal. didn’t you see the movie A Christmas Story when Flicks tongue stuck to the flag pole?

@john65pennington
This is a wood deck.
I just thought this was an interesting question.
Something other than political confrontations. Something we all would be interested in.